Question 1

The Ski Patrol at Criner Mountain Ski Resort has determined the following probability distribution for the number of skiers that are injured each weekend:  Based on this information,the standard deviation for the number of injuries per weekend is 2.25.

Accepted Answer

A) True 
 B)False  False

Question 2

Many people believe that they can tell the difference between Coke and Pepsi.Other people say that the two brands can't be distinguished.To test this,a random sample of 20 adults was selected to participate in a test.After being blindfolded,each person was given a small taste of either Coke or Pepsi and asked to indicate which brand soft drink it was.Suppose 14 people correctly identified the soft drink brand.Which of the following conclusions would be warranted under the circumstance?

Accepted Answer

A)  Since the chance of getting 14 correct is 0.0370,which is quite small,the study shows that people are not able to identify brands effectively.
B)  Since the probability of getting 14 or more correct is 0.0577,which is quite low,this means that people are not effective in identifying the soft drink brand.
C)  Since the probability of getting 14 or more correct is 0.0577,which is quite low,the conclusion could be that people are effective at identifying soft drink brands.
D)  The expected value for this binomial distribution is very close to 14 so this supports that people cannot tell the difference. C

Question 3

A warehouse contains 5 parts made by the Stafford Company and 8 parts made by the Wilson Company.If an employee selects 3 of the parts from the warehouse at random,the probability that all 3 parts are from the Wilson Company is approximately .1958.

Accepted Answer

A) True 
 B)False  True

Question 4

Many people believe that they can tell the difference between Coke and Pepsi.Other people say that the two brands can't be distinguished.To test this,a random sample of 20 adults was selected to participate in a test.After being blindfolded,each person was given a small taste of either Coke or Pepsi and asked to indicate which brand soft drink it was.If people really can't tell the difference,the probability that fewer than 6 people will guess correctly is:

Accepted Answer

A)  0.0148.
B)  approximately 0.02.
C)  0.0307.
D)  0.0514.

Question 5

The number of customers who enter a bank is thought to be Poisson distributed with a mean equal to 10 per hour.What are the chances that no customers will arrive in a 15-minute period?

Accepted Answer

A)  Approximately zero
B)  0.0067
C)  0.0821
D)  0.0250

Question 6

What is the difference between a discrete random variable and a continuous random variable?

Accepted Answer

The answer of What is the difference between a discrete...

Question 7

A store sells 6 different models of cell phones and have found that they sell an equal number of each model.The probability distribution that would describe this random variable is called:

Accepted Answer

A)  uniform distribution.
B)  Poisson distribution.
C)  continuous distribution.
D)  relative frequency distribution.

Question 8

The Cromwell Construction Company has the opportunity to enter into a contract to build a mountain road.The following table shows the probability distribution for the profit that could occur if it takes the contract:  Based on this information,the expected profit for the company if it takes the contract is $60,000.

Accepted Answer

A) True 
 B)False

Question 9

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day:  This distribution is an example of:

Accepted Answer

A)  a uniform distribution.
B)  a continuous probability distribution.
C)  a discrete probability distribution.
D)  an expected value distribution.

Question 10

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day:  The probability of having less than 2 accidents on a given day is:

Accepted Answer

A)  0.30.
B)  0.75.
C)  0.45.
D)  0.25.

Question 11

A sales rep for a national clothing company makes 4 calls per day.Based on historical records,the following probability distribution describes the number of successful calls each day:  The expected number of successful sales calls per day is:

Accepted Answer

A)  2.00.
B)  1.15.
C)  1.90.
D)  2.50.

Question 12

If cars arrive to a service center randomly and independently at a rate of 5 per hour on average,what is the probability that exactly 5 cars will arrive during a given hour?

Accepted Answer

A)  0.1755
B)  0.6160
C)  0.1277
D)  Essentially zero

Question 13

Madam Helga claims to be psychic.A national TV talk personality plans to test her in a live TV broadcast.The process will entail asking Madam Helga a series of 20 independent questions with yes/no answerers.The questions would be of the nature that she could not have any way of knowing the answer from prior knowledge.Suppose that Madam Helga correctly answered 15 of the 20 questions,which of the following would be a viable conclusion to reach?

Accepted Answer

A)  Because the probability of guessing 15 or more correctly is 0.0207,it is unlikely that she is guessing at the questions and may,in fact,have some special ability.
B)  Because the probability of getting 15 or more correct is 0.0207,it is likely that she is just guessing at the questions.
C)  If she were guessing,15 is within one standard deviation of the mean and therefore she must not have any special psychic abilities.
D)  Because the probability of guessing exactly 15 correct is 0.0148,she must just be guessing.

Question 14

When a market research manager records the number of potential customers who were surveyed indicating that they like the product design,the random variable number who like the design is a discrete random variable.

Accepted Answer

A) True 
 B)False

Question 15

A construction company has found it has a probability of 0.10 of winning each time it bids on a project.The probability of winning a given number of projects out of 12 bids could be determined with a binomial distribution.

Accepted Answer

A) True 
 B)False

Question 16

The Cromwell Construction Company has the opportunity to enter into a contract to build a mountain road.The following table shows the probability distribution for the profit that could occur if it takes the contract:  Based on this information,the profit standard deviation for the company if it takes the contract is $11,235.

Accepted Answer

A) True 
 B)False

Question 17

If the standard deviation for a Poisson distribution is known to be 3,the expected value of that Poison distribution is:

Accepted Answer

A)  3.
B)  about 1.73.
C)  9.
D)  Can't be determined without more information.

Question 18

When a single die is rolled,each of the six sides are equally likely.This is an example of a uniform distribution.

Accepted Answer

A) True 
 B)False

Question 19

The Ace Construction Company has entered into a contract to widen a street in Boston.The possible payoffs for this project have been determined by management.The probabilities for these payoffs could be determined using a binomial distribution.

Accepted Answer

A) True 
 B)False

Question 20

A sales rep for a national clothing company makes 4 calls per day.Based on historical records,the following probability distribution describes the number of successful calls each day:  Based on this information,the probability that the sales rep will have a total of 2 successful calls in a two-day period is:

Accepted Answer

A)  0.60.
B)  0.09.
C)  0.15.
D)  0.06.

Exam 5: Discrete Probability Distributions

The Ski Patrol at Criner Mountain Ski Resort has determined the following probability distribution for the number of skiers that are injured each weekend: Based on this information,the standard deviation for the number of injuries per weekend is 2.25.

A warehouse contains 5 parts made by the Stafford Company and 8 parts made by the Wilson Company.If an employee selects 3 of the parts from the warehouse at random,the probability that all 3 parts are from the Wilson Company is approximately .1958.

The number of customers who enter a bank is thought to be Poisson distributed with a mean equal to 10 per hour.What are the chances that no customers will arrive in a 15-minute period?

What is the difference between a discrete random variable and a continuous random variable?

A store sells 6 different models of cell phones and have found that they sell an equal number of each model.The probability distribution that would describe this random variable is called:

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day: This distribution is an example of:

The following probability distribution has been assessed for the number of accidents that occur in a Midwestern city each day: The probability of having less than 2 accidents on a given day is:

A sales rep for a national clothing company makes 4 calls per day.Based on historical records,the following probability distribution describes the number of successful calls each day: The expected number of successful sales calls per day is:

If cars arrive to a service center randomly and independently at a rate of 5 per hour on average,what is the probability that exactly 5 cars will arrive during a given hour?

When a market research manager records the number of potential customers who were surveyed indicating that they like the product design,the random variable number who like the design is a discrete random variable.

A construction company has found it has a probability of 0.10 of winning each time it bids on a project.The probability of winning a given number of projects out of 12 bids could be determined with a binomial distribution.

If the standard deviation for a Poisson distribution is known to be 3,the expected value of that Poison distribution is:

When a single die is rolled,each of the six sides are equally likely.This is an example of a uniform distribution.

The Ace Construction Company has entered into a contract to widen a street in Boston.The possible payoffs for this project have been determined by management.The probabilities for these payoffs could be determined using a binomial distribution.