Question 1

In a Poisson distribution, the variance is equal to ___________.

Accepted Answer

A)   nπ
B)   -x 
D)    " class="answers-bank-image d-inline" rel="preload" >
C)   e-x
D)   -x 
D)    " class="answers-bank-image d-inline" rel="preload" > A

Question 2

Which one of the following is NOT a condition of the binomial distribution?

Accepted Answer

A)   Independent trials
B)   Only two outcomes
C)   The probability of success remains constant from trial to trial
D)   Sampling at least 10 trials D

Question 3

A statistics professor receives an average of five e-mail messages per day from students. Assume the number of messages approximates a Poisson distribution. What is the probability that on a randomly selected day she will have five messages?

Accepted Answer

A)   0.0067
B)   0.8750
C)   0.1755
D)   1.0000 C

Question 4

When observing a checkout line at a food store, the average number of people served is 30 per hour. Using the Poisson distribution, what is the probability that no (zero) people check out in any given hour?

Accepted Answer

The answer of When observing a checkout line at a...

Question 5

David's gasoline station offers 4 cents off per gallon if the customer pays in cash and does not use a credit card. Past evidence indicates that 40% of all customers pay in cash. During a one-hour period, 15 customers buy gasoline at this station. What is the probability that at least 10 pay in cash?

Accepted Answer

A)   0.024
B)   0.033
C)   0.009
D)   0.976

Question 6

Affirmative action commitments by many organizations have led to an increase in the number of women in executive positions. Satellite Office Systems has vacancies for two executives that it will fill from among four women and six men. What is the probability that no woman is selected?

Accepted Answer

A)   1/5
B)   1/3
C)   2/15
D)   8/15

Question 7

A random variable with a Poisson distribution has one of _______ mutually exclusive values.

Accepted Answer

The answer of A random variable with a Poisson distribution...

Question 8

A company is studying the number of daily debit card purchases. There were 20 purchases and the probability of a debit card purchase is 0.5. Of the 20 purchases, what is the expected value of the number of debit card purchases?

Accepted Answer

The answer of A company is studying the number of...

Question 9

A random variable represents the outcome of an experiment.

Accepted Answer

A) True 
 B)False

Question 10

Sponsors of a local charity decided to attract wealthy patrons to its $500-a-plate dinner by allowing each patron to buy a set of 20 tickets for the gaming tables. The chance of winning a prize for each of the 20 plays is 50-50. If you bought 20 tickets, what is the chance of winning 15 or more prizes?

Accepted Answer

A)   0.250
B)   0.021
C)   0.006
D)   0.750

Question 11

Affirmative action commitments by many organizations have led to an increase in the number of women in executive positions. Satellite Office Systems has vacancies for two executives that it will fill from among four women and six men.
What is the probability that exactly one woman is selected?

Accepted Answer

The answer of Affirmative action commitments by many organizations have...

Question 12

To construct a binomial distribution, it is necessary to know the total number of trials and the probability of success on each trial.

Accepted Answer

A) True 
 B)False

Question 13

The variance of a probability distribution is based on the sum or squared differences from the mean.

Accepted Answer

A) True 
 B)False

Question 14

The marketing department of a nationally known cereal maker plans to conduct a national survey to find out whether or not consumers of flake cereals can distinguish one of their favorite flake cereals. To test the questionnaire and procedure to be used, eight persons were asked to cooperate in an experiment. Five very small bowls of flake cereals were placed in front of a person. The bowls were labeled A, B, C, D and

Accepted Answer

A)   0.168
B)   0.009
C)   0.788
D)   0.125
E)   The person was informed that only one bowl contained his or her favorite flake cereal. Suppose that the eight persons in the experiment were unable to identify their favorite cereal and just guessed which bowl it was in. What is the probability that none of the eight guessed correctly?

Question 15

Carlson Jewelers permits the return of their diamond wedding rings, provided the return occurs within two weeks of the purchase date. Their records reveal that 10% of the diamond wedding rings are returned. Five different customers buy a wedding ring. What is the probability that none of the customers return a ring?

Accepted Answer

A)   0.250
B)   0.073
C)   0.590
D)   0.500

Question 16

Data show that the weight of an offensive linesman may be any weight between 200 and 350 pounds. The distribution of weight is based on a ______________.

Accepted Answer

A)   continuous random variable
B)   discrete random variable
C)   qualitative variable
D)   All apply.

Question 17

For the following distribution:  What is the mean of the distribution?

Accepted Answer

A)   1
B)   2.5
C)   1.604
D)   3

Question 18

For a binomial distribution, explain why

Accepted Answer

The answer of For a binomial distribution, explain why ...

Question 19

The variance measures the skewness of a probability distribution.

Accepted Answer

A) True 
 B)False

Question 20

If n = 900 and π = ⅓, the variance of this binomial distribution is ______.

Accepted Answer

The answer of If n = 900 and π =...

Exam 6: Discrete Probability Distributions

In a Poisson distribution, the variance is equal to ___________.

Which one of the following is NOT a condition of the binomial distribution?

A statistics professor receives an average of five e-mail messages per day from students. Assume the number of messages approximates a Poisson distribution. What is the probability that on a randomly selected day she will have five messages?

When observing a checkout line at a food store, the average number of people served is 30 per hour. Using the Poisson distribution, what is the probability that no (zero) people check out in any given hour?

Affirmative action commitments by many organizations have led to an increase in the number of women in executive positions. Satellite Office Systems has vacancies for two executives that it will fill from among four women and six men. What is the probability that no woman is selected?

A random variable with a Poisson distribution has one of _______ mutually exclusive values.

A company is studying the number of daily debit card purchases. There were 20 purchases and the probability of a debit card purchase is 0.5. Of the 20 purchases, what is the expected value of the number of debit card purchases?

A random variable represents the outcome of an experiment.

Affirmative action commitments by many organizations have led to an increase in the number of women in executive positions. Satellite Office Systems has vacancies for two executives that it will fill from among four women and six men. What is the probability that exactly one woman is selected?

To construct a binomial distribution, it is necessary to know the total number of trials and the probability of success on each trial.

The variance of a probability distribution is based on the sum or squared differences from the mean.

Data show that the weight of an offensive linesman may be any weight between 200 and 350 pounds. The distribution of weight is based on a ______________.

For the following distribution: What is the mean of the distribution?

For a binomial distribution, explain why

The variance measures the skewness of a probability distribution.

If n = 900 and π = ⅓, the variance of this binomial distribution is ______.