Question 1

A vaccine is 95 percent effective.What is the probability that it is not effective for more than one out of 20 individuals?

Accepted Answer

A) .7359 
B) .3585 
C) .2641 
D) .3774 
A) .7359 
B) .3585 
C) .2641 
D) .3774

Question 2

In a binomial distribution,the random variable X is continuous.

Accepted Answer

A) True 
 B)False

Question 3

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.If you mail eight local letters,what is the average number you expect to be delivered the next day?

Accepted Answer

A) 3.6 
B) 4.0 
C) 7.2 
D) 2.7 
A) 3.6 
B) 4.0 
C) 7.2 
D) 2.7

Question 4

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find P(X ≤ 1).

Accepted Answer

A) .0870 
B) .2592 
C) .0778 
D) .3370 
A) .0870 
B) .2592 
C) .0778 
D) .3370

Question 5

An important part of the customer service responsibilities of a cable company relates to the speed with which trouble in service can be repaired.Historically,the data show that the likelihood is 0.75 that troubles in a residential service can be repaired on the same day.For the first five troubles reported on a given day,what is the probability that fewer than two troubles will be repaired on the same day?

Accepted Answer

A) .6328 
B) .0010 
C) .0156 
D) .0146 
A) .6328 
B) .0010 
C) .0156 
D) .0146

Question 6

A total of 50 raffle tickets are sold for a contest to win a car.If you purchase one ticket,what are your odds against winning?

Accepted Answer

A) 49 to 1 
B) 50 to 1 
C) .05 
D) .01 
A) 49 to 1 
B) 50 to 1 
C) .05 
D) .01

Question 7

According to data from the state blood program,40 percent of all individuals have group A blood.If six individuals give blood,find the probability that at least 3 of the individuals have group A blood.

Accepted Answer

A) .8208 
B) .5443 
C) .4557 
D) .1792 
A) .8208 
B) .5443 
C) .4557 
D) .1792

Question 8

It is known that 15 percent of all college freshmen at Ivey University leave after their first year.Calculate the interval that contains 99.73 percent of the students who remain if we are looking at a random sample of 300 Ivey University freshmen.

Accepted Answer

A)  $\left[ \begin{array} { l l } 
236.45 & 273.55
\end{array} ]\right.$ 
B)  $\left[ \begin{array} { l l } 
26.45 & 63.55
\end{array} \right]$ 
C)  $\left[ \begin{array} { l l } 
110.25 & 369.75
\end{array} \right]$ 
D)  $\left[ \begin{array} { l l } 
38.82 & 51.18
\end{array} \right]$ 
A)  $\left[ \begin{array} { l l } 
236.45 & 273.55
\end{array} ]\right.$ 
B)  $\left[ \begin{array} { l l } 
26.45 & 63.55
\end{array} \right]$ 
C)  $\left[ \begin{array} { l l } 
110.25 & 369.75
\end{array} \right]$ 
D)  $\left[ \begin{array} { l l } 
38.82 & 51.18
\end{array} \right]$

Question 9

Which of the following distributions can be used to solve the following problem? The average number of cars arriving at a drive-through fast-food restaurant is three in 10 minutes.What is the probability that exactly 4 cars will arrive in a five-minute interval?

Accepted Answer

A) Binomial 
B) Poisson 
C) Both of these 
D) None of these 
A) Binomial 
B) Poisson 
C) Both of these 
D) None of these

Question 10

Historical data show that the average number of patient arrivals at the intensive care unit of General Hospital is 3 patients every two hours.Assume that the patient arrivals are distributed according to Poisson distribution.Determine the probability of 6 patients arriving in a five-hour period.

Accepted Answer

A) .136 
B) .109 
C) .246 
D) .001 
A) .136 
B) .109 
C) .246 
D) .001

Question 11

During off hours,cars arrive at a tollbooth on the East-West toll road at an average rate of 0.5 cars per minute.The arrivals are distributed according to the Poisson distribution.What is the probability that during the next minute,three cars will arrive?

Accepted Answer

A) .0758 
B) .1255 
C) .0126 
D) .0613 
A) .0758 
B) .1255 
C) .0126 
D) .0613

Question 12

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find P(X > 4).

Accepted Answer

A) .0102 
B) .0778 
C) .0870 
D) .3370 
A) .0102 
B) .0778 
C) .0870 
D) .3370

Question 13

Which one of the following statements is not an assumption of the binomial distribution?

Accepted Answer

A) Sampling is with replacement. 
B) The experiment consists of n identical trials. 
C) The probability of success remains constant from trial to trial. 
D) Trials are independent of each other. 
E) Each trial results in one of two mutually exclusive outcomes. 
A) Sampling is with replacement. 
B) The experiment consists of n identical trials. 
C) The probability of success remains constant from trial to trial. 
D) Trials are independent of each other. 
E) Each trial results in one of two mutually exclusive outcomes.

Question 14

A random variable that is defined to be the total number of successes in n trials is a __________ random variable.

Accepted Answer

A) Binomial 
B) Poisson 
C) Hypergeometric 
D) Continuous 
A) Binomial 
B) Poisson 
C) Hypergeometric 
D) Continuous

Question 15

The number of ways to arrange x successes among n trials is equal to

Accepted Answer

A)  $\frac { n ! } { x ! ( n - x ) ! }$ 
B)  $\frac { n ! } { ( n - x ) ! }$ 
C)  $n / x$ 
D)  $n ! /x! $ 
A)  $\frac { n ! } { x ! ( n - x ) ! }$ 
B)  $\frac { n ! } { ( n - x ) ! }$ 
C)  $n / x$ 
D)  $n ! /x! $

Question 16

Consider the experiment of tossing a fair coin three times and observing the number of heads that result (X = number of heads).What is the variance for this distribution?

Accepted Answer

A) 1.5 
B) 1.22 
C) 0.75 
D) 0.87 
A) 1.5 
B) 1.22 
C) 0.75 
D) 0.87

Question 17

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the variance.

Accepted Answer

A) 5.0 
B) 1.2 
C) 2.0 
D) 1.1 
A) 5.0 
B) 1.2 
C) 2.0 
D) 1.1

Question 18

Of all individual tax returns,37 percent include errors made by the taxpayer.If IRS examiners are assigned randomly selected returns in batches of 12,find the mean and standard deviation for the number of erroneous returns per batch.

Accepted Answer

A)  $\mu = 2.80 , \sigma = 1.67$ 
B)  $\mu = 4.44 , \sigma = 1.67$ 
C)  $\mu = 4.44 , \sigma = 2.80$ 
D)  $\mu = 7.56 , \sigma = 2.80$ 
A)  $\mu = 2.80 , \sigma = 1.67$ 
B)  $\mu = 4.44 , \sigma = 1.67$ 
C)  $\mu = 4.44 , \sigma = 2.80$ 
D)  $\mu = 7.56 , \sigma = 2.80$

Question 19

Three candidates run for different offices in different counties.Each has a one in three chance of being elected in his/her county.What is the probability that at least one of them will be elected?

Accepted Answer

A) .2963 
B) .7037 
C) .33 
D) .667 
A) .2963 
B) .7037 
C) .33 
D) .667

Question 20

X has the following probability distribution P(X): $\begin{array} { l l l l l } 
\mathrm { X } & 1 & 2 & 3 & 4 \
\mathrm { P } ( \mathrm { X } ) & .1 & .5 & .2 & .2
\end{array}$
Compute the expected value of X.

Accepted Answer

A) 2.5 
B) 1.0 
C) 1.6 
D) 0.6 
A) 2.5 
B) 1.0 
C) 1.6 
D) 0.6

A vaccine is 95 percent effective.What is the probability that it is not effective for more than one out of 20 individuals?

In a binomial distribution,the random variable X is continuous.

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.If you mail eight local letters,what is the average number you expect to be delivered the next day?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find P(X ≤ 1).

A total of 50 raffle tickets are sold for a contest to win a car.If you purchase one ticket,what are your odds against winning?

According to data from the state blood program,40 percent of all individuals have group A blood.If six individuals give blood,find the probability that at least 3 of the individuals have group A blood.

It is known that 15 percent of all college freshmen at Ivey University leave after their first year.Calculate the interval that contains 99.73 percent of the students who remain if we are looking at a random sample of 300 Ivey University freshmen.

Which of the following distributions can be used to solve the following problem? The average number of cars arriving at a drive-through fast-food restaurant is three in 10 minutes.What is the probability that exactly 4 cars will arrive in a five-minute interval?

Historical data show that the average number of patient arrivals at the intensive care unit of General Hospital is 3 patients every two hours.Assume that the patient arrivals are distributed according to Poisson distribution.Determine the probability of 6 patients arriving in a five-hour period.

During off hours,cars arrive at a tollbooth on the East-West toll road at an average rate of 0.5 cars per minute.The arrivals are distributed according to the Poisson distribution.What is the probability that during the next minute,three cars will arrive?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find P(X > 4).

Which one of the following statements is not an assumption of the binomial distribution?

A random variable that is defined to be the total number of successes in n trials is a __________ random variable.

The number of ways to arrange x successes among n trials is equal to

Consider the experiment of tossing a fair coin three times and observing the number of heads that result (X = number of heads).What is the variance for this distribution?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the variance.

Of all individual tax returns,37 percent include errors made by the taxpayer.If IRS examiners are assigned randomly selected returns in batches of 12,find the mean and standard deviation for the number of erroneous returns per batch.

Three candidates run for different offices in different counties.Each has a one in three chance of being elected in his/her county.What is the probability that at least one of them will be elected?

X has the following probability distribution P(X): 1 2 3 4 () .1 .5 .2 .2 Compute the expected value of X.

An Introduction to Business Statistics

Descriptive Statistics: Tabular and Graphical Methods

Descriptive Statistics: Numerical Methods

Probability

Continuous Random Variables

Sampling and Sampling Distributions

Confidence Intervals

Hypothesis Testing

Comparing Two Means and Two Proportions

Filters

Exam 5: Discrete Random Variables

A vaccine is 95 percent effective.What is the probability that it is not effective for more than one out of 20 individuals?

In a binomial distribution,the random variable X is continuous.

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.If you mail eight local letters,what is the average number you expect to be delivered the next day?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find P(X ≤ 1).

A total of 50 raffle tickets are sold for a contest to win a car.If you purchase one ticket,what are your odds against winning?

According to data from the state blood program,40 percent of all individuals have group A blood.If six individuals give blood,find the probability that at least 3 of the individuals have group A blood.

It is known that 15 percent of all college freshmen at Ivey University leave after their first year.Calculate the interval that contains 99.73 percent of the students who remain if we are looking at a random sample of 300 Ivey University freshmen.

Which of the following distributions can be used to solve the following problem? The average number of cars arriving at a drive-through fast-food restaurant is three in 10 minutes.What is the probability that exactly 4 cars will arrive in a five-minute interval?

Historical data show that the average number of patient arrivals at the intensive care unit of General Hospital is 3 patients every two hours.Assume that the patient arrivals are distributed according to Poisson distribution.Determine the probability of 6 patients arriving in a five-hour period.

During off hours,cars arrive at a tollbooth on the East-West toll road at an average rate of 0.5 cars per minute.The arrivals are distributed according to the Poisson distribution.What is the probability that during the next minute,three cars will arrive?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find P(X > 4).

Which one of the following statements is not an assumption of the binomial distribution?

A random variable that is defined to be the total number of successes in n trials is a __________ random variable.

The number of ways to arrange x successes among n trials is equal to

Consider the experiment of tossing a fair coin three times and observing the number of heads that result (X = number of heads).What is the variance for this distribution?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the variance.

Of all individual tax returns,37 percent include errors made by the taxpayer.If IRS examiners are assigned randomly selected returns in batches of 12,find the mean and standard deviation for the number of erroneous returns per batch.

Three candidates run for different offices in different counties.Each has a one in three chance of being elected in his/her county.What is the probability that at least one of them will be elected?

X has the following probability distribution P(X): 1 2 3 4 () .1 .5 .2 .2 Compute the expected value of X.

An Introduction to Business Statistics

Descriptive Statistics: Tabular and Graphical Methods

Descriptive Statistics: Numerical Methods

Probability

Continuous Random Variables

Sampling and Sampling Distributions

Confidence Intervals

Hypothesis Testing

Comparing Two Means and Two Proportions

Filters