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# ESTATISTICA

DisciplinaEstatística II678 materiais8.560 seguidores
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```Revisar envio do teste: Atividade - Statistics 4

Usuário
ANDRESA JACIELLY FERREIRA DA SILVA
Curso
Estatística
Teste
18/09/19 15:50
18/09/19 16:07
Status
3 em 10 pontos
Tempo decorrido
17 minutos
· Pergunta 1
0 em 1 pontos

A large insurance company wanted to estimate \u3bc, 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.
Skills:
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.
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.
&quot;multiple choice&quot; question: select the correct answer.
Which of the following will produce a narrower confidence interval than the one in Question #2?

Using a random sample of 600 claims (instead of 225)
Resposta Correta:

None of the above. The width of the confidence interval does not depend on the sample size

· 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.
&quot;Fill in the blank&quot; question: select the correct answer. Complete the following sentences:The appropriate hypotheses in this case are:

Ha:  between birth order and delinquent behavior.
Resposta Correta:

There is no relationship.

· Pergunta 3
0 em 1 pontos

Skill: Carry out the chi-square test for the independence of two categorical variables and draw meaningful conclusions.
&quot;multiple choice&quot; question: select the correct answer. When the Chi-square test for independence is carried out, the researchers find that the P-value of the test is 0.01. Which of the following is the appropriate conclusion at the 0.05 significance level?

The data provided enough evidence to conclude that birth order and delinquent behavior are related.
Resposta Correta:

The data provided enough evidence to conclude that birth order and delinquent behavior are independent.

· Pergunta 4
0 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
&quot;multiple choice&quot; question: select the correct answer. Suppose that we would like to test:H0:\u3bc=10Ha:\u3bc\u226010at the 5% significance level. In addition, suppose that based on the collected data the 95% confidence interval for \u3bc is (8.4, 11.1). Which of the following is correct?

Since 10 falls inside the confidence interval we cannot reject H0.
Resposta Correta:

Since 10 falls inside the confidence interval we can reject H0.

· 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
&quot;multiple choice&quot; 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).

Since P\u2212value=0.003<0.05, we conclude that the results of the study do not provide sufficient evidence that Method 1 is more effective than method 2.
Resposta Correta:

Since P\u2212value=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 6
1 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
&quot;multiple choice&quot; 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?

H0: \u3bc1 \u2212 \u3bc2 =\u20090
Ha: \u3bc1 \u2212 \u3bc2 >\u20090
Resposta Correta:

H0: \u3bc1 \u2212 \u3bc2 =\u20090
Ha: \u3bc1 \u2212 \u3bc2 >\u20090
Feedback da resposta:
This is correct.

· Pergunta 7
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 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 \u3bc, 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 \u3c3=4.3 ml.
Skill: Carry out the hypothesis test for the population mean and draw conclusions in context
&quot;multiple choice&quot; question: select the correct answer. Which of the following are the correct null and alternative hypotheses in this case?

H0: \u3bc=752  ;  Ha: \u3bc\u2260752
Resposta Correta:

H0: \u3bc=752  ;  Ha: \u3bc\u2260752
Feedback da resposta:
This is correct.

· Pergunta 8
1 em 1 pontos

Skill: Carry out the paired t-test when appropriate and draw meaningful conclusions
&quot;multiple choice&quot; 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?