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Prévia do material em texto

This is correct. This is the only incorrect statement.
A 2015 CNN Money article provided the following information about the social class distribution of U.S. adults.
Apply probability rules in order to find the likelihood of an event
"Fill in the blank" question: select the correct answer.
Two U.S. adults are chosen at random.Let A be the event that the first adult belongs to the Middle ClassLet B be the event that the second adult belongs to the Lower class.
Complete the following sentences:
Events A and B are
.Events A and B are
		Resposta Selecionada:
	 
Independent
	Resposta Correta:
	 
Independent
	Feedback da resposta:
	This is correct. Since the two chosen are from a large population (of all U.S. adults), the social class of the first adults has no effect on the social class of the second chosen adult.
Pergunta 2
0 em 1 pontos
	
	
	
	This is correct. This is the only incorrect statement.
A 2015 CNN Money article provided the following information about the social class distribution of U.S. adults.
Apply probability rules in order to find the likelihood of an event
"multiple choice" question: select the correct answer.
Two U.S. adults are chosen at random.
Which of the following is the probability that first chosen is Middle Class and the second chosen is Lower Class? In other words, which of the following is P(A and B), where events A and B are as defined in Question #8.
	
	
	
	
		Resposta Selecionada:
	 
2*(.50 + .29)
	Resposta Correta:
	 
.50 * .29
	
	
	
Pergunta 3
1 em 1 pontos
	
	
	
	The probability table below summarizes the information that a large cable company provides about its customers:
Where:
T is the event that a randomly chosen customer subscribes to TV service
I is the event that a randomly chosen customer subscribes to Internet service
Create a probability table to organize and summarize information and use it to find probabilities
"multiple choice" question: select the correct answer.
What is the correct representation and probability of the event that a customer subscribes only to TV service?
	
	
	
	
		Resposta Selecionada:
	 
P(T and Not I) = .05
	Resposta Correta:
	 
P(T and Not I) = .05
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 4
0 em 1 pontos
	
	
	
	Fit the binomial model when appropriate, and use it to perform probability calculations.
"multiple choice" question: select the correct answer.
The National Survey on Drug Use and Health also reported that 21% of males in the same age group (12-20) are binge drinkers.
Suppose that in addition to the 10 randomly chosen females, a random sample 10 males from the same age group is chosen (to a total of 20).
Let the random variable Y be the total number of males and females (out of 20) who are binge drinkers.
Which of the following is true regarding the random variable Y?
	
	
	
	
		Resposta Selecionada:
	 
Y does not have a binomial distribution since the number of trials n is not fixed.
	Resposta Correta:
	 
Y has a binomial distribution with n=20 and p=.18
	
	
	
Pergunta 5
0 em 1 pontos
	
	
	
	A large cable company provides the following information regarding its customers:
· 50% of all customers subscribe to internet service.
· If a customer is an internet subscriber, there is 64% chance that he/she is also a phone subscriber.
· If a customer is a phone subscriber, there is 80% chance that he/she is also an internet subscriber.
Let A be the event that a customer subscribes to internet service
Let B be the event that a customer subscribes to phone service
Determine whether two events are independent
"multiple choice" question: select the correct answer.
Are the two subscriptions (phone, Internet) independent of each other?
	
	
	
	
		Resposta Selecionada:
	 
No, since P(A|B) = .80 is not equal to P(B|A) = .64
	Resposta Correta:
	 
No, since P(A)=.50 is not equal to P(A|B) = .80
	
	
	
Pergunta 6
0 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, in one of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Find the probability of events in the case when all outcomes are equally likely.
"multiple choice" question: select the correct answer.
Assume that each time that the family goes out to eat they choose one of the three restaurants at random, and again, let A be the event that on a given the family eats in R2 exactly once. What is P(A)?
	
	
	
	
		Resposta Selecionada:
	 
1/4
	Resposta Correta:
	 
4/9
	
	
	
Pergunta 7
0 em 1 pontos
	
	
	
	The weekly cost of maintenance and repairs for a company has a normal distribution with mean μ=$5500 and standard deviation σ=$400.
Note: For questions 19 and 20 you will need to use the Normal Table linked here
Use the normal distribution as an approximation to the binomial distribution
"Fill in the blank" question: select the correct answer.
In this case, X can be approximated by a normal distribution with mean μ=
and standard deviation σ=
	
	
	
	
		Resposta Selecionada:
	 
1600
	Resposta Correta:
	 
160
	
	
	
Pergunta 8
0 em 1 pontos
	
	
	
	Airlines sometimes overbook flights. Suppose that for a plane with 111 seats an airline takes 115 reservations. Let the random variable X be the number of people who actually show up (out of the 115 who bought a ticket). From past experience the probability distribution of X is given in the following table:
x 108 109 110 111 112 113 114 115
P(X=x) 0.14 0.16 0.24 0.20 0.13 0.06 0.05 0.02
Find the mean and variance of a discrete random variable, and apply these concepts for solving real world problems.
"multiple choice" question: select the correct answer.
On average, how many people show up to the flight?
(some answers are rounded to one decimal place)
	
	
	
	
		Resposta Selecionada:
	 
111.5
	Resposta Correta:
	 
110.5
	
	
	
Pergunta 9
1 em 1 pontos
	
	
	
	Find the mean and variance of a linear transformation of a random variable, and the mean and variance of the sum of two independent random variables.
"multiple choice" question: select the correct answer.
Based on accumulated data, a propane gas company determined that the random variable X, the number of gallon required to fill a customer’s propane tank, has mean μx=300 gallons and standard deviation σx=40 gallons. The company charges the customer $25 service fee plus $2.50 per gallon of propone.
What is the mean and standard deviation of the amount that a customer is billed for?
	
	
	
	
		Resposta Selecionada:
	 
mean = $775, standard deviation = $100
	Resposta Correta:
	 
mean = $775, standard deviation = $100
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 10
0 em 1 pontos
	
	
	
	Understand how relative frequency can be used to estimate the probability of an event and apply this approach in practice.
"multiple choice" question: select the correct answer.
1250 randomly chosen individuals from a certain population are tested for the presence of the HIV virus, and 20 are found to be carriers of the virus. Based on this information, what is the estimate of P(V), the probability that a randomly chosen person from this population carries the HIV virus?
	
	
	
	
		Resposta Selecionada:
	 
.20
	Resposta Correta:
	 
.016
	
Pergunta 1
1 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, inone of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Find the probability of events in the case when all outcomes are equally likely.
"multiple choice" question: select the correct answer.
Assume that each time that the family goes out to eat they choose one of the three restaurants at random, and again, let A be the event that on a given the family eats in R2 exactly once. What is P(A)?
	
	
	
	
		Resposta Selecionada:
	 
4/9
	Resposta Correta:
	 
4/9
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 2
1 em 1 pontos
	
	
	
	Skill: Determine the sampling distribution of the sample proportion and the sample mean in a given situation and apply it to determine likelihoods.
"multiple choice" question: select the correct answer.
There is 95% chance in a random sample of n=84 card users, the proportion of those who pay their bills in full every month will be:
	
	
	
	
		Resposta Selecionada:
	 
Between .20 and .40
	Resposta Correta:
	 
Between .20 and .40
	Feedback da resposta:
	This is correct. When n=84, the mean and standard deviation of the sampling distribution are: p = .30 and p(1−p)n−−−−−√=.3(1−.3)84−−−−−−√=0.05, respectively.By the standard deviation rule, there is 95% chance that the sample proportion will be within two standard deviations of its mean. In other words, between .30 – 2(.05) = .20 and .30 + 2(.05) = .40.
	
	
	
Pergunta 3
1 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, in one of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Determine the sample space of a random experiment and identify which outcomes are included in a particular event
"multiple choice" question: select the correct answer.
Let A be the event that on a given month the family eats in R2 exactly once. What are the possible outcomes for this event?
	
	
	
	
		Resposta Selecionada:
	 
{ (R1, R2) (R2, R1) (R2, R3) (R3, R2) }
	Resposta Correta:
	 
{ (R1, R2) (R2, R1) (R2, R3) (R3, R2) }
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 4
0 em 1 pontos
	
	
	
	A patient with a failing heart is waiting for a heart transplant. If a suitable transplant is found, the patient’s chances of survival are much higher than the patient’s chances of survival if a suitable transplant is not found.
Let T be the event that a suitable Transplant is found.
Let S be the event that the patient Survives
The following probability tree summarizes the patient’s chances of finding a suitable transplant and survival.
Use the tree to answer the following questions:
Use Probability Trees as a tool to find probabilities
Use the general multiplication rule to find P(A and B)
"multiple choice" question: select the correct answer.
What is the probability that a suitable transplant is found and the patient survives?
	
	
	
	
		Resposta Selecionada:
	 
.075
	Resposta Correta:
	 
.225
	
	
	
Pergunta 5
0 em 1 pontos
	
	
	
	Airlines sometimes overbook flights. Suppose that for a plane with 111 seats an airline takes 115 reservations. Let the random variable X be the number of people who actually show up (out of the 115 who bought a ticket). From past experience the probability distribution of X is given in the following table:
x 108 109 110 111 112 113 114 115
P(X=x) 0.14 0.16 0.24 0.20 0.13 0.06 0.05 0.02
	
	
	
	
		Resposta Selecionada:
	 
0.26
	Resposta Correta:
	 
0.74
	
	
	
Pergunta 6
1 em 1 pontos
	
	
	
	Skill: Determine the sampling distribution of the sample proportion and the sample mean in a given situation and apply it to determine likelihoods.
"multiple choice" question: select the correct answer. 
Is it safe to assume that the sampling distribution of pˆ is approximately normal for random samples of size n=21?
	
	
	
	
		Resposta Selecionada:
	 
No, since n*p is not greater than 10.
	Resposta Correta:
	 
No, since n*p is not greater than 10.
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 7
0 em 1 pontos
	
	
	
	A patient with a failing heart is waiting for a heart transplant. If a suitable transplant is found, the patient’s chances of survival are much higher than the patient’s chances of survival if a suitable transplant is not found.
Let T be the event that a suitable Transplant is found.
Let S be the event that the patient Survives
The following probability tree summarizes the patient’s chances of finding a suitable transplant and survival.
Use the tree to answer the following questions:
Use Probability Trees as a tool to find probabilities
"multiple choice" question: select the correct answer.
Given that the patient survives, what is the probability that a suitable transplant was found (what is P(T|S))? (Some answers were rounded).
	
	
	
	
		Resposta Selecionada:
	 
.225
	Resposta Correta:
	 
.616
	
	
	
Pergunta 8
1 em 1 pontos
	
	
	
	The National Survey on Drug and Health reported that 15% females in the age group of 12 to 20 years old are binge drinkers.
A random sample of 10 females from this age group is chosen, and let the random variable X be the number of females (out of 10) who are binge drinkers.
Fit the binomial model when appropriate, and use it to perform probability calculations.
"multiple choice" question: select the correct answer.
Which of the following is the correct probability distribution function of X?
	
	
	
	
		Resposta Selecionada:
	 
P(X=x)=10!x!(10−x)! ⋅ 0.15x ⋅ 0.8510−x x=0, 1, 2, 3...9, 10
	Resposta Correta:
	 
P(X=x)=10!x!(10−x)! ⋅ 0.15x ⋅ 0.8510−x x=0, 1, 2, 3...9, 10
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 9
0 em 1 pontos
	
	
	
	Skill: Determine the sampling distribution of the sample proportion and the sample mean in a given situation and apply it to determine likelihoods.
"multiple choice" question: select the correct answer. 
What is the mean and standard deviation of the sampling distribution of x¯, the average number of defects in a sample of size n=225?
	
	
	
	
		Resposta Selecionada:
	 [Sem Resposta]
	Resposta Correta:
	 
Mean = 3.6, standard deviation = 0.5
	
	
	
Pergunta 10
0 em 1 pontos
	
	
	
	Airlines sometimes overbook flights. Suppose that for a plane with 111 seats an airline takes 115 reservations. Let the random variable X be the number of people who actually show up (out of the 115 who bought a ticket). From past experience the probability distribution of X is given in the following table:
x 108 109 110 111 112 113 114 115
P(X=x) 0.14 0.16 0.24 0.20 0.13 0.06 0.05 0.02
Find the probability distribution function of a discrete random variable and use it to find probabilities
"multiple choice" question: select the correct answer.
Given that an hour before the flight 109 passengers have already showed up to the flight, what is the probability that a total of 111 or less passengers will eventually show up to the flight? (Some answers are rounded to 2 decimal places).
	
	
	
	
		Resposta Selecionada:
	 
0.74
	Resposta Correta:
	 
0.70
	
	
	
Pergunta 1
1 em 1 pontos
	
	
	
	Find the probability distribution function of a discrete random variable and use it to find probabilities
"multiple choice"question: select the correct answer.
	
	
	
	
		Resposta Selecionada:
	 
0.7
	Resposta Correta:
	 
0.7
	Feedback da resposta:
	This is correct. P(X >2) = P(X=3) + P(X=4) = 6/20 + 8/20 = 14/20 = 0.7
	
	
	
Pergunta 2
0 em 1 pontos
	
	
	
	The weekly cost of maintenance and repairs for a company has a normal distribution with mean μ=$5500 and standard deviation σ=$400.
Note: For questions 19 and 20 you will need to use the Normal Table linked here
Use the normal distribution as an approximation to the binomial distribution
"multiple choice" question: select the correct answer.
Use the normal approximation and the Standard Deviation Rule to complete the following sentence:
There is 99.7% chance that X, the number of smokers (out of 1600), will be:
	
	
	
	
		Resposta Selecionada:
	 
between 148 and 172
	Resposta Correta:
	 
between 124 and 196
	
	
	
Pergunta 3
0 em 1 pontos
	
	
	
	An epidemiological study investigated the prevalence of two contagious diseases ( Disease 1 and Disease 2) in the U.S.
Let A be the event that an individual contracts Disease 1
Let B be the event that an individual contracts Disease 2
Determine whether two events are independent
"multiple choice" question: select the correct answer.
Recall that the epidemiological study reported the following:
· There is 15% chance of contracting Disease 1 (Event A)
· There is 10% chance of contracting Disease 2 (Event B)
· There is 3% chance of contracting both Disease 1 and Disease 2
Are the two diseases being contracted independently of each other (are events A, B independent)?
	
	
	
	
		Resposta Selecionada:
	 
Yes, since these are two contagious diseases
	Resposta Correta:
	 
No, since P(A and B)=.03 is not equal to P(A)*P(B)=.15*.10=.015
	
	
	
Pergunta 4
0 em 1 pontos
	
	
	
	A lot of research is conducted on the sleeping habits of U.S. adults. One study reported that X, the amount of sleep per night of U.S. adults follows a normal distribution with mean μ=7.5 hours and standard deviation σ=1.2 hours.
Find probabilities associated with the normal distribution.
"multiple choice" question: select the correct answer.
Using the Standard Deviation Rule, 2.5% of U.S. adults sleep less than how many hours per night?
	
	
	
	
		Resposta Selecionada:
	 
7.5
	Resposta Correta:
	 
5.1
	
	
	
Pergunta 5
1 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, in one of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Determine the sample space of a random experiment and identify which outcomes are included in a particular event
"multiple choice" question: select the correct answer.
Which of the following is the correct sample space in this case?
	
	
	
	
		Resposta Selecionada:
	 
S= { (R1, R1) (R2, R2) (R3, R3) (R1, R2) (R2, R1) (R1, R3) (R3, R1) (R2, R3) (R3, R2) }
	Resposta Correta:
	 
S= { (R1, R1) (R2, R2) (R3, R3) (R1, R2) (R2, R1) (R1, R3) (R3, R1) (R2, R3) (R3, R2) }
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 6
0 em 1 pontos
	
	
	
	The weekly cost of maintenance and repairs for a company has a normal distribution with mean μ=$5500 and standard deviation σ=$400.
Note: For questions 19 and 20 you will need to use the Normal Table linked here
Find probabilities associated with the normal distribution.
"multiple choice" question: select the correct answer.
How much should be budgeted for weekly maintenance and repair so that there is only 1.5% chance that the cost will exceed the budgeted amount.
	
	
	
	
		Resposta Selecionada:
	 
5916
	Resposta Correta:
	 
6368
	
	
	
Pergunta 7
0 em 1 pontos
	
	
	
	A lot of research is conducted on the sleeping habits of U.S. adults. One study reported that X, the amount of sleep per night of U.S. adults follows a normal distribution with mean μ=7.5 hours and standard deviation σ=1.2 hours.
P(8.5<X≤9.5)
Find probabilities associated with the normal distribution.
"multiple choice" question: select the correct answer.
Using the Standard Deviation Rule, what is the probability that a randomly chosen U.S. adult sleeps more than 8.7 hours per night?
	
	
	
	
		Resposta Selecionada:
	 
0.025
	Resposta Correta:
	 
0.16
	
	
	
Pergunta 8
0 em 1 pontos
	
	
	
	The following three probability histograms represent the probability distributions of the random variables X, Y, and W.
As is evident from the probability histograms, the mean of all three random variables is 5.
Find the mean and variance of a discrete random variable, and apply these concepts for solving real world problems.
"multiple choice" question: select the correct answer.
Which of the three random variables has the smallest standard deviation?
	
	
	
	
		Resposta Selecionada:
	 
W
	Resposta Correta:
	 
Y
	
	
	
Pergunta 9
0 em 1 pontos
	
	
	
	Based on the Journal of the American Medical Association, weights of all newborn babies in U.S. follow a normal distribution with a mean of 3420 grams and standard deviation of 500 grams. The weights of 625 randomly selected newborns were recorded and it was found that the average and standard deviation in this sample were 3450 grams and 490, respectively.
Skill: Distinguish between a parameter and a statistic and recognize the concept of sampling variability.
"multiple choice" question: select the correct answer. 
μ, x¯, σ, and s (in this order are):
	
	
	
	
		Resposta Selecionada:
	 
3450, 625, 490, 500
	Resposta Correta:
	 
3420, 3450, 500, 490
	
	
	
Pergunta 10
0 em 1 pontos
	
	
	
	This is correct. This is the only incorrect statement.
A 2015 CNN Money article provided the following information about the social class distribution of U.S. adults.
Apply probability rules in order to find the likelihood of an event
"multiple choice" question: select the correct answer.
Four U.S. adults are selected at random. What is the probability that at least one of them belongs to the Upper Class?
	
	
	
	
		Resposta Selecionada:
	 
.214
	Resposta Correta:
	 
1 – .794
	
	This is correct. This is the only incorrect statement.
A 2015 CNN Money article provided the following information about the social class distribution of U.S. adults.
Apply probability rules in order to find the likelihood of an event
"multiple choice" question: select the correct answer.
Two U.S. adults are chosen at random. What is the probability that both adults belong to the same social class?
		Resposta Selecionada:
	 
.29 * .29 + .50 * .50 + .21 * .21
	Resposta Correta:
	 
.29 * .29 + .50 * .50 + .21 * .21
	Feedback da resposta:
	This is correct. P(Both belong to the same social class) = P(Both Lower class or Both Middle class or Both Upper class) = [disjoint]P(Both Lower class) + P(Both Middle class) + P(Both Upper class) = [independence].29 * .29 + .50 * .50 + .21 * .21
Pergunta 2
0 em 1 pontos
	
	
	
	
An epidemiological study investigated the prevalence of two contagious diseases ( Disease 1 and Disease 2) in the U.S.
Let A be the event that an individual contracts Disease 1
Let B be the event that an individual contracts Disease 2
Understand the reasoning behind the concept of conditional probability, calculate conditional probabilities and interpret them.
"multiple choice" question: select the correct answer.
What is the interpretation of P(B|A) in the context of this study?
	
	
	
	
		RespostaSelecionada:
	 
The probability that an individual contracts Disease 1 given that he/she has already contracted Disease 2.
	Resposta Correta:
	 
(D) and (E) are both interpretations of P(B|A).
	
	
	
Pergunta 3
1 em 1 pontos
	
	
	
	Find the probability distribution function of a discrete random variable and use it to find probabilities
"multiple choice" question: select the correct answer.
	
	
	
	
		Resposta Selecionada:
	 
0.7
	Resposta Correta:
	 
0.7
	Feedback da resposta:
	This is correct. P(X >2) = P(X=3) + P(X=4) = 6/20 + 8/20 = 14/20 = 0.7
	
	
	
Pergunta 4
0 em 1 pontos
	
	
	
	Understand how probability quantifies uncertainty and relate the probability of an event to the likelihood of the event occurring.
"multiple choice" question: select the correct answer.
Which of the following is true regarding a probability of an event P(A)?
	
	
	
	
		Resposta Selecionada:
	 
P(A)<1
	Resposta Correta:
	 
0≤P(A)≤1
	
	
	
Pergunta 5
1 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, in one of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Find the probability of events in the case when all outcomes are equally likely.
"multiple choice" question: select the correct answer.
Assume that each time that the family goes out to eat they choose one of the three restaurants at random, and again, let A be the event that on a given the family eats in R2 exactly once. What is P(A)?
	
	
	
	
		Resposta Selecionada:
	 
4/9
	Resposta Correta:
	 
4/9
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 6
0 em 1 pontos
	
	
	
	A large cable company provides the following information regarding its customers:
· 50% of all customers subscribe to internet service.
· If a customer is an internet subscriber, there is 64% chance that he/she is also a phone subscriber.
· If a customer is a phone subscriber, there is 80% chance that he/she is also an internet subscriber.
Let A be the event that a customer subscribes to internet service
Let B be the event that a customer subscribes to phone service
Use the general multiplication rule to find P(A and B)
"multiple choice" question: select the correct answer.
What is the probability that a customer subscribes to both internet and phone service?
	
	
	
	
		Resposta Selecionada:
	 
P(A) * P(B), but since we do not know P(B), there not enough information to answer this question.
	Resposta Correta:
	 
P(A) * P(B|A) = .50 * .64 = .32
	
	
	
Pergunta 7
0 em 1 pontos
	
	
	
	A patient with a failing heart is waiting for a heart transplant. If a suitable transplant is found, the patient’s chances of survival are much higher than the patient’s chances of survival if a suitable transplant is not found.
Let T be the event that a suitable Transplant is found.
Let S be the event that the patient Survives
The following probability tree summarizes the patient’s chances of finding a suitable transplant and survival.
Use the tree to answer the following questions:
Use Probability Trees as a tool to find probabilities
"multiple choice" question: select the correct answer.
What is the probability that the patient survives? (what is P(S)?)
	
	
	
	
		Resposta Selecionada:
	 
.15
	Resposta Correta:
	 
.365
	
	
	
Pergunta 8
0 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, in one of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Apply probability rules in order to find the likelihood of an event
"multiple choice" question: select the correct answer.
Let B be the event that on a given month the family eats in R1 at least once.In context, the complement of event B, ‘Not B’ is the event that:
	
	
	
	
		Resposta Selecionada:
	 
in a given month, the family eats at R1 at most once
	Resposta Correta:
	 
in a given month, the family eats at R1 twice
	
	
	
Pergunta 9
0 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, in one of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Apply probability rules in order to find the likelihood of an event
Find the probability of events in the case when all outcomes are equally likely.
Determine the sample space of a random experiment and identify which outcomes are included in a particular event
"multiple choice" question: select the correct answer.
A fair four sided die with the numbers 1,2,3, and 4 is rolled twice. Thus, for example, the outcome (4, 1) denotes that the die landed on a 4 on the first roll and on 1 on the second. What is the probability that the sum of the numbers showing in the two rolls is 3?
	
	
	
	
		Resposta Selecionada:
	 [Sem Resposta]
	Resposta Correta:
	 
1/8
	
	
	
Pergunta 10
1 em 1 pontos
	
	
	
	A lot of research is conducted on the sleeping habits of U.S. adults. One study reported that X, the amount of sleep per night of U.S. adults follows a normal distribution with mean μ=7.5 hours and standard deviation σ=1.2 hours.
Skill:
Find probabilities associated with the normal distribution.
"multiple choice" question: select the correct answer.
Which of the following is the correct interpretation of the fact that the value x has a Z-score of 0.25
	
	
	
	
		Resposta Selecionada:
	 
x is .25 standard deviations above the mean.
	Resposta Correta:
	 
x is .25 standard deviations above the mean.
	Feedback da resposta:
	This is correct.
	
	
	
	
	
	
	
	
	
	
	
Pergunta 1
1 em 1 pontos
	
	
	
	Based on the Journal of the American Medical Association, weights of all newborn babies in U.S. follow a normal distribution with a mean of 3420 grams and standard deviation of 500 grams. The weights of 625 randomly selected newborns were recorded and it was found that the average and standard deviation in this sample were 3450 grams and 490, respectively.
Skill: Distinguish between a parameter and a statistic and recognize the concept of sampling variability.
"multiple choice" question: select the correct answer.
Which of the following is a statistic?
	
	
	
	
		Resposta Selecionada:
	 
3420
	Resposta Correta:
	 
3420
	Feedback da resposta:
	This is correct. 3450 and 490 are the sample mean and sample standard deviation, respectively, and therefore both are statistics.
	
	
	
Pergunta 2
0 em 1 pontos
	
	
	
	The weekly cost of maintenance and repairs for a company has a normal distribution with mean μ=$5500 and standard deviation σ=$400.
Note: For questions 19 and 20 you will need to use the Normal Table linked here
Find probabilities associated with the normal distribution.
"multiple choice" question: select the correct answer.
If $6200 is budgeted for the next week, what is the probability that the cost will exceed the budgeted amount?Resposta Selecionada:
	 
.9599
	Resposta Correta:
	 
.0401
	
	
	
Pergunta 3
1 em 1 pontos
	
	
	
	A family eats out twice a month – once during the first week of the month and once during the third week of the month, in one of the three local restaurants: R1, R2, or R3. Thus the outcome (R3, R2) denotes that on a given month the family eats in R3 during the first week of the month and in R2 during the third week of the month. It is possible for the family to eat at the same restaurant both on the first week and on the third week of the month.
Determine the sample space of a random experiment and identify which outcomes are included in a particular event
"multiple choice" question: select the correct answer.
Let A be the event that on a given month the family eats in R2 exactly once. What are the possible outcomes for this event?
	
	
	
	
		Resposta Selecionada:
	 
{ (R1, R2) (R2, R1) (R2, R3) (R3, R2) }
	Resposta Correta:
	 
{ (R1, R2) (R2, R1) (R2, R3) (R3, R2) }
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 4
1 em 1 pontos
	
	
	
	The weekly cost of maintenance and repairs for a company has a normal distribution with mean μ=$5500 and standard deviation σ=$400.
Note: For questions 19 and 20 you will need to use the Normal Table linked here
Use the normal distribution as an approximation to the binomial distribution
"Fill in the blank" question: select the correct answer.
In this case, X can be approximated by a normal distribution with mean μ=
and standard deviation σ=
	
	
	
	
		Resposta Selecionada:
	 
160
	Resposta Correta:
	 
160
	Feedback da resposta:
	This is correct. The mean of the normal approximation is the mean of the binomial distribution which is np=1600*0.1=160.
	
	
	
Pergunta 5
1 em 1 pontos
	
	
	
	A lot of research is conducted on the sleeping habits of U.S. adults. One study reported that X, the amount of sleep per night of U.S. adults follows a normal distribution with mean μ=7.5 hours and standard deviation σ=1.2 hours.
Find probabilities associated with the normal distribution.
"multiple choice" question: select the correct answer.
Using the Standard Deviation Rule, 2.5% of U.S. adults sleep less than how many hours per night?
	
	
	
	
		Resposta Selecionada:
	 
5.1
	Resposta Correta:
	 
5.1
	Feedback da resposta:
	This is correct. By the Standard deviation Rule 95% of U.S. adults sleep between 7.5 – 2(1.2) = 5.1 hours and 7.5 + 2(1.2)=9.9 hours. Therefore, 2.5% of U.S. adults sleep less than 5.1 hours.
	
	
	
Pergunta 6
0 em 1 pontos
	
	
	
	An epidemiological study investigated the prevalence of two contagious diseases ( Disease 1 and Disease 2) in the U.S.
Let A be the event that an individual contracts Disease 1
Let B be the event that an individual contracts Disease 2
Understand the reasoning behind the concept of conditional probability, calculate conditional probabilities and interpret them.
"multiple choice" question: select the correct answer.
Of the individuals who did not contract Disease 2, what proportion will not contract Disease 1?
	
	
	
	
		Resposta Selecionada:
	 
.78/.90
	Resposta Correta:
	 
.78/.85
	
	
	
Pergunta 7
1 em 1 pontos
	
	
	
	Based on the Journal of the American Medical Association, weights of all newborn babies in U.S. follow a normal distribution with a mean of 3420 grams and standard deviation of 500 grams. The weights of 625 randomly selected newborns were recorded and it was found that the average and standard deviation in this sample were 3450 grams and 490, respectively.
Skill: Distinguish between a parameter and a statistic and recognize the concept of sampling variability. "multiple choice" question: select the correct answer. 
Which of the following is a parameter?
	
	
	
	
		Resposta Selecionada:
	 
500
	Resposta Correta:
	 
500
	Feedback da resposta:
	This is correct. 500 is the population standard deviation and therefore a parameter.
	
	
	
Pergunta 8
1 em 1 pontos
	
	
	
	A patient with a failing heart is waiting for a heart transplant. If a suitable transplant is found, the patient’s chances of survival are much higher than the patient’s chances of survival if a suitable transplant is not found.
Let T be the event that a suitable Transplant is found.
Let S be the event that the patient Survives
The following probability tree summarizes the patient’s chances of finding a suitable transplant and survival.
Use the tree to answer the following questions:
Use Probability Trees as a tool to find probabilities
"multiple choice" question: select the correct answer.
What is the probability that the patient survives? (what is P(S)?)
	
	
	
	
		Resposta Selecionada:
	 
.365
	Resposta Correta:
	 
.365
	Feedback da resposta:
	This is correct. P(S)=.30*.75 + .70*.20=.365
	
	
	
Pergunta 9
1 em 1 pontos
	
	
	
	Skill: Determine the sampling distribution of the sample proportion and the sample mean in a given situation and apply it to determine likelihoods.
"multiple choice" question: select the correct answer. 
Is it safe to assume that the sampling distribution of pˆ is approximately normal for random samples of size n=21?
	
	
	
	
		Resposta Selecionada:
	 
No, since n*p is not greater than 10.
	Resposta Correta:
	 
No, since n*p is not greater than 10.
	Feedback da resposta:
	This is correct.
	
	
	
Pergunta 10
0 em 1 pontos
	
	
	
	Fit the binomial model when appropriate, and use it to perform probability calculations.
"multiple choice" question: select the correct answer.
What are the mean and standard deviation of X, the number of females out of the 10 chosen who are binge drinkers?
	
	
	
	
		Resposta Selecionada:
	 
μx=10(0.15) −−−−−−−−√ , σx=10(0.15)(0.85)
	Resposta Correta:
	 
μx=10(0.15) , σx=10(0.15)(0.85)−−−−−−−−−−−−√

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