Statistics_TOTAL_FMU

Prévia do material em texto

Pergunta 1
0 em 1 pontos
	
	
	
	Skill: Carry out the chi-square test for the independence of two categorical variables and draw meaningful conclusions.
"multiple choice" question: select the correct answer. 
The Chi-square test statistic is calculated using the observed and expected counts of the cells of the two-way table. Suppose that for one particular cell:
Observed count = 35
Expected count =25
What is the contribution of this cell to the Chi-square test statistic? 
	
	
	
	
		Resposta Selecionada:
	 
2.86
	Resposta Correta:
	 
4
	
	
	
Pergunta 2
0 em 1 pontos
	
	
	
	Skill: Determine the likelihood of making type I and type II errors, and explain how to reduce them, in context.
"multiple choice" question: select the correct answer. What can be done in order to reduce the risk of Type II error?
	
	
	
	
		Resposta Selecionada:
	 
Choose a smaller significance level (for example, 0.01 instead of 0.05).
	Resposta Correta:
	 
Increase the sample size.
	
	
	
Pergunta 3
0 em 1 pontos
	
	
	
	A recent Gallup poll concerning abortion reported that 30% (.30) of the sampled U.S. adults said that abortion should be legal in all cases. The report added that the margin of error at the 95% confidence level was 4% (.04).
Skill: Calculate interpret the confidence interval for the population proportion p, and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. If the Gallup researchers had wanted the margin of error (at the 95% confidence level) to be only 3.5% (0.035) instead of 4%, what sample size should they have used?(Some answers are rounded to one decimal place). 
	
	
	
	
		Resposta Selecionada:
	 
28.6
	Resposta Correta:
	 
817
	
	
	
Pergunta 4
0 em 1 pontos
	
	
	
	The question whether birth order affects juvenile delinquency was examined in a large study using a high school population. A random sample of 1,060 boys attending public school were given a questionnaire that measured delinquent behavior and then classified each boy as either 'Yes' or 'No'. Each boy also indicated his birth order: the oldest, in between, or the youngest. The results are summarized in the following two-way table:
	
	
	
	
		Resposta Selecionada:
	 
birth order and delinquent behavior are not independent.
	Resposta Correta:
	 
birth order and delinquent behavior are independent.
	
	
	
Pergunta 5
0 em 1 pontos
	
	
	
	Fine 'motor control' of the hands and fingers is an important milestone for little children. Such motor control skills are often taught in pre-school, but the outcome might differ depending on the teaching method.One particular study was conducted to compare the effectiveness of two teaching methods for teaching a specific motor skill. The subjects, 70 pre-school children, were each randomly assigned to be taught by either Method 1 or Method 2. The outcome (the response) is a performance measure of the motor skill (higher is better) as measured by an outside expert who did not know which teaching method each child was assigned to.
Skill: Carry out the two-sample t-test for comparing two population means when appropriate and draw meaningful conclusions
"multiple choice" question: select the correct answer. Method 1 is a newer method and according to its developers, is more effective than Method 2. Does the data provide enough evidence to support the developers' claim?
Let µ1 and µ2 be the mean motor skill performance measure of all children taught by method 1 and method 2, respectively.Which of the following are the appropriate hypotheses in this case?
	
	
	
	
		Resposta Selecionada:
	 
H0: μ1 − μ2 > 0
Ha: μ1 − μ2 = 0
	Resposta Correta:
	 
H0: μ1 − μ2 = 0
Ha: μ1 − μ2 > 0
	
	
	
Pergunta 6
1 em 1 pontos
	
	
	
	It was found that 25% of community college students in the state of California do not complete their Intro Stats class (i.e., either withdraw mid-course or fail). In an effort to reduce the non-completion rate, a new hybrid course format (on-line materials + face-to-face instructions) was designed to replace the traditional course. To test its effectiveness, a random sample of 300 California community college students who took the Intro Stats course in the new format was chosen and it was found that 66 of them (22%) did not complete the course.Do these data provide enough evidence to conclude that when the course is taught in the new format the non-completion rate is reduced? Let p be the proportion of all community college students in the state of California who took Intro Stats in the new format and did not complete the course.
Skill: Carry out the hypothesis test for the population proportion and draw conclusions in context. "multiple choice" question: select the correct answer.
The p-value is this case is above 10%. Which of the following is the appropriate conclusion at the 5% significance level?
	
	
	
	
		Resposta Selecionada:
	
We cannot reject H0. The data do not provide enough evidence to conclude that the new course format reduces the non-completion rate.
	Resposta Correta:
	
We cannot reject H0. The data do not provide enough evidence to conclude that the new course format reduces the non-completion rate.
	Feedback da resposta:
	This is correct. Since p-value > 5%, we cannot reject H0.
	
	
	
Pergunta 7
0 em 1 pontos
	
	
	
	Skill: Carry out the hypothesis test for the population proportion and draw conclusions in context. "multiple choice" question: select the correct answer.
Recall that in order to assess whether the new Intro Stats course format reduces the non-completion rate, a random sample of 300 California community college students who took the course in the new format was chosen and it was found that 66 of them (22%) did not complete the course.Which of the following would have provided stronger evidence that the new course format reduces the non-completion? In other words, which of the following would have resulted in a smaller p-value for this test?
	
	
	
	
		Resposta Selecionada:
	 
A random sample of of 300 students was chosen and 60 of them (20%) did not complete the course.
	Resposta Correta:
	 
Both (B) and (C) are correct
	
	
	
Pergunta 8
1 em 1 pontos
	
	
	
	A large insurance company wanted to estimate μ, the mean claim size (in $) on an auto insurance policy. A random sample of 225 claims was chosen and it was found that the average claim size was $2875. From past experience the population standard deviation is assumed to be $1350.
Skill: Calculate interpret the confidence interval for the population mean , and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. Which of the following is the 95% confidence interval for μ?
	
	
	
	
		Resposta Selecionada:
	 
(2695, 3055)
	Resposta Correta:
	 
(2695, 3055)
	Feedback da resposta:
	This is correct. The 95% confidence interval is: x¯±2⋅σn√=2875±2⋅1350225√=2875±180=(2695, 3055)
	
	
	
Pergunta 9
1 em 1 pontos
	
	
	
	A random sample of 700 U.S. adults was asked the following question:Do you approve or disapprove of the way Donald Trump is handling his job as president?280 of the 700 responded that they approve. 
Skill: Calculate interpret the confidence interval for the population proportion p, and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. Which of the following is the correct 90% confidence interval for p, the proportion of all U.S. adults who approve of the way Donald Trump is handling his job as president?(Answers are rounded to two decimal places).
	
	
	
	
		Resposta Selecionada:(0.37, 0.43) 
	Resposta Correta:
	 
(0.37, 0.43) 
	Feedback da resposta:
	This is correct. ρˆ±1.645⋅ρˆ(1−ρˆn−−−−−√=.40±1.645⋅.40(.60)700−−−−−√≈.40±.03=(.37, .43)
	
	
	
Pergunta 10
1 em 1 pontos
	
	
	
	Skill: Carry out the paired t-test when appropriate and draw meaningful conclusions
"multiple choice" question: select the correct answer. The researchers analyze the data and obtain the following output:
Which of the following is an appropriate conclusion based on the output?
	
	
	
	
		Resposta Selecionada:
	
The data provided sufficient evidence to reject H0. Thus, the researcher can conclude that the depression scores of students in the San Francisco and Bay area are, on average, higher following the earthquake.
	Resposta Correta:
	
The data provided sufficient evidence to reject H0. Thus, the researcher can conclude that the depression scores of students in the San Francisco and Bay area are, on average, higher following the earthquake.
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 1
1 em 1 pontos
	
	
	
	Skill: Perform inference for the linear relationship between two quantitative variables
"multiple choice" question: select the correct answer. Since the data displayed a linear relationship, the correlation coefficient was calculated and was found to be r=−0.81. Based on the scatterplot and the value of the correlation coefficient, it would make sense to test the significance of this observed linear relationship between IQ and DI. The appropriate hypotheses are: 
	
	
	
	
		Resposta Selecionada:
	 
H0: IQ and DI are not linearly relatedHa: IQ and DI are linearly related.
	Resposta Correta:
	 
H0: IQ and DI are not linearly relatedHa: IQ and DI are linearly related.
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 2
0 em 1 pontos
	
	
	
	The question whether birth order affects juvenile delinquency was examined in a large study using a high school population. A random sample of 1,060 boys attending public school were given a questionnaire that measured delinquent behavior and then classified each boy as either 'Yes' or 'No'. Each boy also indicated his birth order: the oldest, in between, or the youngest. The results are summarized in the following two-way table:
To test whether the data provides significant evidence for a relationship between birth order and delinquent behavior, we will use the Chi-square test for independence.
Skill: Carry out the chi-square test for the independence of two categorical variables and draw meaningful conclusions.
"Fill in the blank" question: select the correct answer. Complete the following sentences:The appropriate hypotheses in this case are: 
	
	
	
	
		Resposta Selecionada:
	 
Ha:  between birth order and delinquent behavior. 
	Resposta Correta:
	 
 There is no relationship.
	
	
	
Pergunta 3
1 em 1 pontos
	
	
	
	Skill: Carry out the hypothesis test for the population proportion and draw conclusions in context. "multiple choice" question: select the correct answer.
In 2015 60% of all U.S. adults supported same-sex marriage. We would like to test whether the proportion of all U.S. adults who support same-sex marriage has increased since then. In a recent poll, 20 U.S. adults were randomly chosen and 13 of them (65%) supported same-sex marriage.Can we safely use the z-test for p in this case?
Which of the following is correct?
	
	
	
	
		Resposta Selecionada:
	 
It is not safe to use the z-test for p in this case since 20*(1-.60) is not large enough.
	Resposta Correta:
	 
It is not safe to use the z-test for p in this case since 20*(1-.60) is not large enough.
	Feedback da resposta:
	This is correct. It is not safe to use the z-test for p in this case since n(1-p0)=20(1-.60)=8 is not at least 10.
	
	
	
Pergunta 4
1 em 1 pontos
	
	
	
	Skill: Carry out the chi-square test for the independence of two categorical variables and draw meaningful conclusions.
"multiple choice" question: select the correct answer. 
The Chi-square test statistic is calculated using the observed and expected counts of the cells of the two-way table. Suppose that for one particular cell:
Observed count = 35
Expected count =25
What is the contribution of this cell to the Chi-square test statistic? 
	
	
	
	
		Resposta Selecionada:
	 
4
	Resposta Correta:
	 
4
	Feedback da resposta:
	This is correct. The contribution to the Chi-square test statistic of this cell is:(Observed count − Expected Count)2 Expected Count=(35−25)225=10025=4.
	
	
	
Pergunta 5
1 em 1 pontos
	
	
	
	It was found that 25% of community college students in the state of California do not complete their Intro Stats class (i.e., either withdraw mid-course or fail). In an effort to reduce the non-completion rate, a new hybrid course format (on-line materials + face-to-face instructions) was designed to replace the traditional course. To test its effectiveness, a random sample of 300 California community college students who took the Intro Stats course in the new format was chosen and it was found that 66 of them (22%) did not complete the course.Do these data provide enough evidence to conclude that when the course is taught in the new format the non-completion rate is reduced? Let p be the proportion of all community college students in the state of California who took Intro Stats in the new format and did not complete the course.
Skill: Carry out the hypothesis test for the population proportion and draw conclusions in context. "multiple choice" question: select the correct answer.
The p-value is this case is above 10%. Which of the following is the appropriate conclusion at the 5% significance level?
	
	
	
	
		Resposta Selecionada:
	
We cannot reject H0. The data do not provide enough evidence to conclude that the new course format reduces the non-completion rate.
	Resposta Correta:
	
We cannot reject H0. The data do not provide enough evidence to conclude that the new course format reduces the non-completion rate.
	Feedback da resposta:
	This is correct. Since p-value > 5%, we cannot reject H0.
	
	
	
Pergunta 6
0 em 1 pontos
	
	
	
	It was found that 25% of community college students in the state of California do not complete their Intro Stats class (i.e., either withdraw mid-course or fail). In an effort to reduce the non-completion rate, a new hybrid course format (on-line materials + face-to-face instructions) was designed to replace the traditional course. To test its effectiveness, a random sample of 300 California community college students who took the Intro Stats course in the new format was chosen and it was found that 66 of them (22%) did not complete the course.Do these data provide enough evidence to conclude that when the course is taught in the new format the non-completion rate is reduced? Let p be the proportion of all community college students in the state of California who took Intro Stats in the new format and did not complete the course.
Skills: Carry out the hypothesis test for the population proportion and draw conclusions in context. Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer.
The p-value in this case is the probability of getting data like that observed or more extreme (i.e., getting an observed non-completion rate of 22% or lower) assuming that:
	
	
	
	
		Resposta Selecionada:
	 
the new course format did reduce the non-completion rate
	Resposta Correta:
	 
the new course format did not reduce the non-completion rate.
	
	
	
Pergunta 7
0 em 1 pontos
	
	
	
	Skill: Perform inference for the linear relationship between two quantitative variables
"multiple choice" question: select the correct answer. The following output is available:Based on the output, which of the following is the appropriate conclusion?
	
	
	
	
		Resposta Selecionada:
	 
The data provide strong evidence that IQ and DI are related.
	Resposta Correta:
	 
The data provide strong evidence that IQ and DI are linearly related.
	
	
	
Pergunta 8
0 em 1 pontos
	
	
	
	A recent Gallup poll concerning abortion reported that 30% (.30) of the sampled U.S. adults said that abortion should be legal in all cases. The report added that the margin of error at the 95% confidence level was 4% (.04).
Skill: Calculate interpret the confidence interval for the population proportion p, and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. Which of the following is the correct interpretation of the margin of error in this case? 
	
	
	
	
		Resposta Selecionada:
	
We are 95% confident that the proportion of all U.S. adults who feel that abortion should be legal in all cases is more than .04 away from .30. 
	Resposta Correta:
	
 We are 95% confident that the proportion of all U.S. adults who feel that abortion should be legal in all cases is no more than .04 away from .30. 
	
	
	
Pergunta 9
0 em 1 pontos
	
	
	
	Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer. The p-value of the test is 0.022. Which of the following is the appropriate conclusion at the 5% significance level?
	
	
	
	
		Resposta Selecionada:
	 
The data provide evidence to reject H0 and conclude that the mean volume dispensed is the required 752ml.
	Resposta Correta:
	 
The data provide evidence to reject H0 and conclude that the mean volume dispensed is not the required 752ml.
	
	
	
Pergunta 10
1 em 1 pontos
	
	
	
	The question whether birth order affects juvenile delinquency was examined in a large study using a high school population. A random sample of 1,060 boys attending public school were given a questionnaire that measured delinquent behavior and then classified each boy as either 'Yes' or 'No'. Each boy also indicated his birth order: the oldest, in between, or the youngest. The results are summarized in the following two-way table:
	
	
	
	
		Resposta Selecionada:
	 
birth order and delinquent behavior are independent.
	Resposta Correta:
	 
birth order and delinquent behavior are independent.
	Feedback da resposta:
	This is correct. Expected counts are calculated assuming that the null hypothesis of the chi-square test is true.
	
	
	
Pergunta 1
1 em 1 pontos
	
	
	
	Skill: Carry out the ANOVA procedure or comparing more than two population means.
"multiple choice" question: select the correct answer. Consistent with the group numbering, let μ1, μ2, and μ3 the mean SAT-Math score of all students who study on their own, work with a tutor, and complete a prep-course, respectively.
Which of the following are the appropriate null and alternative hypotheses?
	
	
	
	
		Resposta Selecionada:
	 
H0: μ1 = μ2 = μ3
Ha: Not all the μ’s are equal 
	Resposta Correta:
	 
H0: μ1 = μ2 = μ3
Ha: Not all the μ’s are equal 
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 2
1 em 1 pontos
	
	
	
	Skills: Carry out the hypothesis test for the population proportion and draw conclusions in context
Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer. Suppose that we would like to test:H0:μ=10Ha:μ≠10at the 5% significance level. In addition, suppose that based on the collected data the 95% confidence interval for μ is (8.4, 11.1). Which of the following is correct?
	
	
	
	
		Resposta Selecionada:
	 
Since 10 falls inside the confidence interval we can reject H0.
	Resposta Correta:
	 
Since 10 falls inside the confidence interval we can reject H0.
	Feedback da resposta:
	This is correct. Since 10 falls inside the confidence interval, it is, based on the data, a plausible value for μ. We therefore cannot reject H0.
	
	
	
Pergunta 3
0 em 1 pontos
	
	
	
	Skill: Carry out the two-sample t-test for comparing two population means when appropriate and draw meaningful conclusions
"multiple choice" question: select the correct answer. Recall that the P-value of the test for assessing whether
Method 1 is more effective than Method 2 for teaching children a motor skill was P-value = 0.003. Which of the following is the appropriate conclusion? (Use significance level of 0.05). 
	
	
	
	
		Resposta Selecionada:
	
Since P−value=0.003<0.05, we conclude that the results of the study provide sufficient evidence that actually Method 2 is more effective than method 1.
	Resposta Correta:
	
Since P−value=0.003<0.05, we conclude that the results of the study provide sufficient evidence that Method 1 is more effective than method 2.
	
	
	
Pergunta 4
0 em 1 pontos
	
	
	
	The Medical College Admission Test (MCAT) is an examination for prospective medical students.Suppose that based on data collected from a random sample of 100 MCAT takers, the 95% confidence interval for μ, the mean MCAT score, was calculated to be (497, 503).
Skill:
Calculate interpret the confidence interval for the population mean , and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. If we were to use the same data to calculate a 90% confidence interval for μ, the mean MCAT score, which of the following could be this interval?
	
	
	
	
		Resposta Selecionada:
	 
(496, 500)
	Resposta Correta:
	 
(498, 502)
	
	
	
Pergunta 5
1 em 1 pontos
	
	
	
	A random sample of 700 U.S. adults was asked the following question:Do you approve or disapprove of the way Donald Trump is handling his job as president?280 of the 700 responded that they approve. 
Skill: Calculate interpret the confidence interval for the population proportion p, and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. Which of the following is the correct 90% confidence interval for p, the proportion of all U.S. adults who approve of the way Donald Trump is handling his job as president?(Answers are rounded to two decimal places).
	
	
	
	
		Resposta Selecionada:
	 
(0.37, 0.43) 
	Resposta Correta:
	 
(0.37, 0.43) 
	Feedback da resposta:
	This is correct. ρˆ±1.645⋅ρˆ(1−ρˆn−−−−−√=.40±1.645⋅.40(.60)700−−−−−√≈.40±.03=(.37, .43)
	
	
	
Pergunta 6
0 em 1 pontos
	
	
	
	Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer. Which of the following is true regarding the t-distribution.
	
	
	
	
		Resposta Selecionada:
	 
The t –distribution is more spread out than the normal distribution.
	Resposta Correta:
	 
All of the above are correct.
	
	
	
Pergunta 7
1 em 1 pontos
	
	
	
	A large insurance company wanted to estimate μ, the mean claim size (in $) on an auto insurance policy. A random sample of 225 claims was chosen and it was found that the average claim size was $2875. From past experience the population standard deviation is assumed to be $1350.
Determine point estimates in simple cases, and make the connection between the sampling distribution of a statistic, and its properties as a point estimator.
"multiple choice" question: select the correct answer. Which of the following is the point estimate for μ?
	
	
	
	
		Resposta Selecionada:
	 
$2875
	Resposta Correta:
	 
$2875
	Feedback da resposta:
	This is correct. The pointestimate for the population mean is the sample mean.
	
	
	
Pergunta 8
0 em 1 pontos
	
	
	
	Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
"Fill in the blank" question: select the correct answer.
Consider the following two scenarios involving hypothesis testing the population mean, and complete the sentences that follow.
I. The mean IQ score of adults is known to be 100. In order to test whether the mean IQ of lawyers is higher than 100, a random sample of 10 lawyers was chosen and their IQ measured and recorded. It was found that for the 10 sampled lawyers the average IQ score was 101.4 with a standard deviation of 14.5. It is known that IQ scores follow a normal distribution.
II. The mean IQ score of adults is known to be 100. In order to test whether the mean IQ of lawyers is higher than 100, a random sample of 10 lawyers was chosen and their IQ measured and recorded. It was found that for the 10 sampled lawyers the average IQ score was 101.4. It is known that IQ scores follow a normal distribution with standard deviation of 15.
Complete the following sentences: In scenario I, the , and therefore the should be used.In scenario II, the , and therefore the should be used.
	
	
	
	
		Resposta Selecionada:
	 
population standard deviation is known
	Resposta Correta:
	 
standard deviation is calculated from the sample
	
	
	
Pergunta 9
0 em 1 pontos
	
	
	
	Skill: Carry out the ANOVA procedure or comparing more than two population means.
"multiple choice" question: select the correct answer. Results of the analysis that was run on the SAT-Math data:
Which of the following is an appropriate conclusion based on the output?
	
	
	
	
		Resposta Selecionada:
	
We can reject H0 and conclude that the data provides strong evidence that performance on the SAT-math is related to the study strategy.
	Resposta Correta:
	 
Both (A) and (B) are are appropriate conclusions.
	
	
	
Pergunta 10
0 em 1 pontos
	
	
	
	Skill: Carry out the paired t-test when appropriate and draw meaningful conclusions
"multiple choice" question: select the correct answer. The researchers analyze the data and obtain the following output:
Which of the following is an appropriate conclusion based on the output?
	
	
	
	
		Resposta Selecionada:
	
The data do not provided sufficient evidence to reject H0. Thus, the researcher cannot conclude that the depression scores of students in the San Francisco and Bay area were, on average, higher following the earthquake.
	Resposta Correta:
	
The data provided sufficient evidence to reject H0. Thus, the researcher can conclude that the depression scores of students in the San Francisco and Bay area are, on average, higher following the earthquake.
	
	
	
Pergunta 1
1 em 1 pontos
	
	
	
	It was found that 25% of community college students in the state of California do not complete their Intro Stats class (i.e., either withdraw mid-course or fail). In an effort to reduce the non-completion rate, a new hybrid course format (on-line materials + face-to-face instructions) was designed to replace the traditional course. To test its effectiveness, a random sample of 300 California community college students who took the Intro Stats course in the new format was chosen and it was found that 66 of them (22%) did not complete the course.Do these data provide enough evidence to conclude that when the course is taught in the new format the non-completion rate is reduced? Let p be the proportion of all community college students in the state of California who took Intro Stats in the new format and did not complete the course.
Skills: Carry out the hypothesis test for the population proportion and draw conclusions in context. Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer.
The p-value in this case is the probability of getting data like that observed or more extreme (i.e., getting an observed non-completion rate of 22% or lower) assuming that:
	
	
	
	
		Resposta Selecionada:
	 
the new course format did not reduce the non-completion rate.
	Resposta Correta:
	 
the new course format did not reduce the non-completion rate.
	Feedback da resposta:
	This is correct. The p-value is calculated assuming that the null hypothesis is true. In this case, therefore, the p-value is calculated assuming that the new course format did not reduce the non-completion rate.
	
	
	
Pergunta 2
1 em 1 pontos
	
	
	
	Skill: Carry out the two-sample t-test for comparing two population means when appropriate and draw meaningful conclusions
"multiple choice" question: select the correct answer. Recall that the P-value of the test for assessing whether
Method 1 is more effective than Method 2 for teaching children a motor skill was P-value = 0.003. Which of the following is the appropriate conclusion? (Use significance level of 0.05). 
	
	
	
	
		Resposta Selecionada:
	 
Since P−value=0.003<0.05, we conclude that the results of the study provide sufficient evidence that Method 1 is more effective than method 2.
	Resposta Correta:
	 
Since P−value=0.003<0.05, we conclude that the results of the study provide sufficient evidence that Method 1 is more effective than method 2.
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 3
1 em 1 pontos
	
	
	
	A random sample of 700 U.S. adults was asked the following question:Do you approve or disapprove of the way Donald Trump is handling his job as president?280 of the 700 responded that they approve. 
Skill: Calculate interpret the confidence interval for the population proportion p, and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. Which of the following is the correct 90% confidence interval for p, the proportion of all U.S. adults who approve of the way Donald Trump is handling his job as president?(Answers are rounded to two decimal places).
	
	
	
	
		Resposta Selecionada:
	 
(0.37, 0.43) 
	Resposta Correta:
	 
(0.37, 0.43) 
	Feedback da resposta:
	This is correct. ρˆ±1.645⋅ρˆ(1−ρˆn−−−−−√=.40±1.645⋅.40(.60)700−−−−−√≈.40±.03=(.37, .43)
	
	
	
Pergunta 4
0 em 1 pontos
	
	
	
	Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer. Which of the following is true regarding the t-distribution.
	
	
	
	
		Resposta Selecionada:
	 
The t –distribution is more spread out than the normal distribution.
	Resposta Correta:
	 
All of the above are correct.
	
	
	
Pergunta 5
0 em 1 pontos
	
	
	
	Skill: Carry out the two-sample t-test for comparing two population means when appropriate and draw meaningful conclusions
"multiple choice" question: select the correct answer. 
When the two-sample t-test is carried out, the researchers find that the test statistic is t = 2.83 and P-value = 0.003 P-value = 0.003 tells us that it would be quite unlikely to get results like that observed in our study (or more extreme) assuming that:
	
	
	
	
		Resposta Selecionada:
	 
There is a difference in effectiveness between the two methods.
	Resposta Correta:
	 
There is no difference in effectiveness between the two methods.
	
	
	
Pergunta 6
1 em 1 pontos
	
	
	
	Wineries use machines that automatically fill the bottles. The amount of wine that the machine dispenses will naturally vary slightly from bottle to bottle. To determine whether the machine is working properly, bottles are occasionally sampled and the volume of wine is measured. A winery in California randomly sampled 5 bottles and found that the average volume in these bottles was747.6 milliliters (ml). If the machine is working properly, bottles should contain 752 ml of wine, on average. Using the data they collected, the winery would like to test whether μ, the mean volume dispensed by the machine differs from this value (752 ml). Suppose that the volume of wine dispensed by the machine is known to have a normal distribution with standard deviation σ=4.3 ml.
Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer. Which of the following is the correct test-statistic in this case?
	
	
	
	
		Resposta Selecionada:
	 
z=747.6−7524.35√/
	Resposta Correta:
	 
z=747.6−7524.35√/
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 7
0 em 1 pontos
	
	
	
	Skill: Carry out the ANOVA procedure or comparing more than two population means.
"multiple choice" question: select the correct answer. Results of the analysis that was run on the SAT-Math data:
Which of the following is an appropriate conclusion based on the output?
	
	
	
	
		Resposta Selecionada:
	
We can reject H0 and conclude that the data provides strong evidence that the three SAT-math score means (representing the three study strategies) are not all equal.
	Resposta Correta:
	 
Both (A) and (B) are are appropriate conclusions.
	
	
	
Pergunta 8
0 em 1 pontos
	
	
	
	A recent Gallup poll concerning abortion reported that 30% (.30) of the sampled U.S. adults said that abortion should be legal in all cases. The report added that the margin of error at the 95% confidence level was 4% (.04).
Skill: Calculate interpret the confidence interval for the population proportion p, and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. If the Gallup researchers had wanted the margin of error (at the 95% confidence level) to be only 3.5% (0.035) instead of 4%, what sample size should they have used?(Some answers are rounded to one decimal place). 
	
	
	
	
		Resposta Selecionada:
	 
816.3
	Resposta Correta:
	 
817
	
	
	
Pergunta 9
1 em 1 pontos
	
	
	
	The Medical College Admission Test (MCAT) is an examination for prospective medical students.Suppose that based on data collected from a random sample of 100 MCAT takers, the 95% confidence interval for μ, the mean MCAT score, was calculated to be (497, 503).
Skill:
Determine point estimates in simple cases, and make the connection between the sampling distribution of a statistic, and its properties as a point estimator.
"multiple choice" question: select the correct answer.
Which of the following is true regarding the sample proportion ρˆ, as a point estimator for the population proportion p?
	
	
	
	
		Resposta Selecionada:
	 
All of the above are true.
	Resposta Correta:
	 
All of the above are true.
	
	
	
Pergunta 10
0 em 1 pontos
	
	
	
	Skill: Carry out the ANOVA procedure or comparing more than two population means.
"multiple choice" question: select the correct answer. The following output provides summary statistics (sample size, mean, and standard deviation) of the the three study-strategy samples:
Based on this information, does the data meet the ANOVA condition of equal population standard deviations?
	
	
	
	
		Resposta Selecionada:
	 
No, since 105.8–73.7>2
	Resposta Correta:
	 
Yes, since
	
	
	
Pergunta 1
0 em 1 pontos
	
	
	
	The Medical College Admission Test (MCAT) is an examination for prospective medical students.Suppose that based on data collected from a random sample of 100 MCAT takers, the 95% confidence interval for μ, the mean MCAT score, was calculated to be (497, 503).
Skill:
Calculate interpret the confidence interval for the population mean , and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer.
Which of the following is the correct interpretation of this confidence interval?
	
	
	
	
		Resposta Selecionada:
	 
There is 95% chance that the average MCAT score of 100 randomly chosen students is between 497 and 503.
	Resposta Correta:
	 
We are 95% confident that the mean MCAT score is covered by the interval (497, 503).
	
	
	
Pergunta 2
1 em 1 pontos
	
	
	
	The Medical College Admission Test (MCAT) is an examination for prospective medical students.Suppose that based on data collected from a random sample of 100 MCAT takers, the 95% confidence interval for μ, the mean MCAT score, was calculated to be (497, 503).
Skill:
Calculate interpret the confidence interval for the population mean , and recognize the effect of level of confidence and sample size on the precision of the interval estimation.
"multiple choice" question: select the correct answer. If we were to use the same data to calculate a 90% confidence interval for μ, the mean MCAT score, which of the following could be this interval?
	
	
	
	
		Resposta Selecionada:
	 
(498, 502)
	Resposta Correta:
	 
(498, 502)
	Feedback da resposta:
	This is correct. The 90% confidence interval calculated using the same data has to be both narrower and, like the 95% confidence interval, centered at the same sample mean (500).
	
	
	
Pergunta 3
1 em 1 pontos
	
	
	
	Skill: Carry out the two-sample t-test for comparing two population means when appropriate and draw meaningful conclusions
"multiple choice" question: select the correct answer. Recall that the P-value of the test for assessing whether
Method 1 is more effective than Method 2 for teaching children a motor skill was P-value = 0.003. Which of the following is the appropriate conclusion? (Use significance level of 0.05). 
	
	
	
	
		Resposta Selecionada:
	
Since P−value=0.003<0.05, we conclude that the results of the study provide sufficient evidence that Method 1 is more effective than method 2.
	Resposta Correta:
	
Since P−value=0.003<0.05, we conclude that the results of the study provide sufficient evidence that Method 1 is more effective than method 2.
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 4
1 em 1 pontos
	
	
	
	Skill: Perform inference for the linear relationship between two quantitative variables
"multiple choice" question: select the correct answer. The observed relationship in the scatterplot means that:
	
	
	
	
		Resposta Selecionada:
	 
The more intelligent the child is (as measured by IQ) the lower the risk of delinquent behavior.
	Resposta Correta:
	 
The more intelligent the child is (as measured by IQ) the lower the risk of delinquent behavior.
	
	
	
Pergunta 5
1 em 1 pontos
	
	
	
	The question whether birth order affects juvenile delinquency was examined in a large study using a high school population. A random sample of 1,060 boys attending public school were given a questionnaire that measured delinquent behavior and then classified each boy as either 'Yes' or 'No'. Each boy also indicated his birth order: the oldest, in between, or the youngest. The results are summarized in the following two-way table:
	
	
	
	
		Resposta Selecionada:
	 
birth order and delinquent behavior are independent.
	Resposta Correta:
	 
birth order and delinquent behavior are independent.
	Feedback da resposta:
	This is correct. Expected counts are calculated assuming that the null hypothesis of the chi-square test is true.
	
	
	
Pergunta 6
1 em 1 pontos
	
	
	
	Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
"Fill in the blank" question: select the correct answer.
Consider the following two scenarios involving hypothesis testing the population mean, and complete the sentences that follow.
I. The meanIQ score of adults is known to be 100. In order to test whether the mean IQ of lawyers is higher than 100, a random sample of 10 lawyers was chosen and their IQ measured and recorded. It was found that for the 10 sampled lawyers the average IQ score was 101.4 with a standard deviation of 14.5. It is known that IQ scores follow a normal distribution.
II. The mean IQ score of adults is known to be 100. In order to test whether the mean IQ of lawyers is higher than 100, a random sample of 10 lawyers was chosen and their IQ measured and recorded. It was found that for the 10 sampled lawyers the average IQ score was 101.4. It is known that IQ scores follow a normal distribution with standard deviation of 15.
Complete the following sentences: In scenario I, the , and therefore the should be used.In scenario II, the , and therefore the should be used.
	
	
	
	
		Resposta Selecionada:
	 
standard deviation is calculated from the sample
	Resposta Correta:
	 
standard deviation is calculated from the sample
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 7
1 em 1 pontos
	
	
	
	Skill: Carry out the ANOVA procedure or comparing more than two population means.
"multiple choice" question: select the correct answer. The following output provides summary statistics (sample size, mean, and standard deviation) of the the three study-strategy samples:
Based on this information, does the data meet the ANOVA condition of equal population standard deviations?
	
	
	
	
		Resposta Selecionada:
	 
Yes, since
	Resposta Correta:
	 
Yes, since
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 8
0 em 1 pontos
	
	
	
	Wineries use machines that automatically fill the bottles. The amount of wine that the machine dispenses will naturally vary slightly from bottle to bottle. To determine whether the machine is working properly, bottles are occasionally sampled and the volume of wine is measured. A winery in California randomly sampled 5 bottles and found that the average volume in these bottles was 747.6 milliliters (ml). If the machine is working properly, bottles should contain 752 ml of wine, on average. Using the data they collected, the winery would like to test whether μ, the mean volume dispensed by the machine differs from this value (752 ml). Suppose that the volume of wine dispensed by the machine is known to have a normal distribution with standard deviation σ=4.3 ml.
Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
"multiple choice" question: select the correct answer. Which of the following are the correct null and alternative hypotheses in this case?
	
	
	
	
		Resposta Selecionada:
	 
H0: x¯=747.6  ;  Ha: x¯<747.6
	Resposta Correta:
	 
H0: μ=752  ;  Ha: μ≠752
	
	
	
Pergunta 9
1 em 1 pontos
	
	
	
	Skill: Determine the likelihood of making type I and type II errors, and explain how to reduce them, in context.
"multiple choice" question: select the correct answer. 
A certain type of lightbulb is advertised to have mean lifetime of 750 hours.A consumer advocacy group would like to check this claims and test:H0: The mean lifetime is the advertised 750 hoursHa: The mean lifetime is less than the advertised 750 hours.The advocacy group chooses at random 40 lightbulbs and records their lifetimes. Based on the data the group concludes that the mean lifetime is less than 750 hours and accuses the manufacturer of the lightbulbs in false advertising. What type of error is possible in this situation?
	
	
	
	
		Resposta Selecionada:
	 
Type I
	Resposta Correta:
	 
Type I
	Feedback da resposta:
	This is correct. It is possible that the data provide evidence that the mean lifetime is less than advertised, when in reality it actually isn’t. In other words, in this situation there is a risk that the consumer advocacy group rejects the null hypothesis by mistake. This is type I error.
	
	
	
Pergunta 10
1 em 1 pontos
	
	
	
	Skill: Carry out the chi-square test for the independence of two categorical variables and draw meaningful conclusions.
"multiple choice" question: select the correct answer. 
The Chi-square test statistic is calculated using the observed and expected counts of the cells of the two-way table. Suppose that for one particular cell:
Observed count = 35
Expected count =25
What is the contribution of this cell to the Chi-square test statistic? 
	
	
	
	
		Resposta Selecionada:
	 
4
	Resposta Correta:
	 
4
	Feedback da resposta:
	This is correct. The contribution to the Chi-square test statistic of this cell is:(Observed count − Expected Count)2 Expected Count=(35−25)225=10025=4.