Question 1

X has the probability distribution: $\begin{array} { l r r r r r } 
\mathrm { X } & - 2 & - 1 & 9 & 1 & 2 \
\mathrm { P } ( \mathrm { X } ) & .2 & .2 & .2 & .2 & .2
\end{array}$
Compute the expected value of X.

Accepted Answer

A) 1.3 
B) 1.0 
C) 2.4 
D) 1.8 
A) 1.3 
B) 1.0 
C) 2.4 
D) 1.8

Question 2

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

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 3

For a discrete probability distribution,the value of p(x)for each value of x falls between -1 and 1.

Accepted Answer

A) True 
 B)False

Question 4

The number of calls coming into a PBX follows a Poisson process with a mean of 120 calls per hour.What is the probability of no calls in a one-minute interval?

Accepted Answer

A) 0 
B) .1353 
C) .4060 
D) .3679 
A) 0 
B) .1353 
C) .4060 
D) .3679

Question 5

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the P(X = 2).

Accepted Answer

A) .2304 
B) .3456 
C) .3072 
D) .5760 
A) .2304 
B) .3456 
C) .3072 
D) .5760

Question 6

When p = .5,the binomial distribution will _________ be symmetric.

Accepted Answer

A) Always 
B) Sometimes 
C) Never 
A) Always 
B) Sometimes 
C) Never

Question 7

If the number of surface nonconformities on a specific size of a metal piece is the discrete random variable in question,then the appropriate probability distribution that can describe the probability of a specific size metal sheet containing 3 nonconformities is most likely given by the binomial distribution.

Accepted Answer

A) True 
 B)False

Question 8

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What is the probability that all 3 of your DVDs will last at least three years?

Accepted Answer

0.7
Feedba

Question 9

The random variable x has a hypergeometric distribution,and the population contains 12 items.If you wanted to find the number of defects in a random sample of 3 selected items when the population contains 5 defects,identify the N,n,and r.

Accepted Answer

A) N = 3,n = 12,r = 5 
B) N = 5,n = 12,r = 7 
C) N = 12,n = 5.r = 3 
D) N = 12,n = 3,r = 5 
A) N = 3,n = 12,r = 5 
B) N = 5,n = 12,r = 7 
C) N = 12,n = 5.r = 3 
D) N = 12,n = 3,r = 5

Question 10

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μx = .16,μy = .07,σx = .11,σy = .11,and σxy2 = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.

Accepted Answer

Mean = .115,Standard deviation

Question 11

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,find the mean number of troubles repaired on the same day.

Accepted Answer

A) 3.75 
B) 0.94 
C) 1.94 
D) 2.50 
A) 3.75 
B) 0.94 
C) 1.94 
D) 2.50

Question 12

If x is a binomial random variable,then the standard deviation of x is given by:

Accepted Answer

A) np 
B) (npq)2 
C) √npq 
D) npq 
A) np 
B) (npq)2 
C) √npq 
D) npq

Question 13

Consider a Poisson distribution with an average of 3 customers per minute at the local grocery store.If X = the number of arrivals per minute,find the expected value of X.

Accepted Answer

A) 3 
B) 9 
C) 1.5 
D) 1.7 
A) 3 
B) 9 
C) 1.5 
D) 1.7

Question 14

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μx = .16,μy = .07,σx = .11,σy = .11,and σxy2 = .0321.Find the mean and standard deviation of the portfolio return: P = .45x + .55y.

Accepted Answer

Mean = .1105;Standard deviatio

Question 15

Depending on the mean of the Poisson distribution,the distribution can either be very skewed to the right or quite symmetrical.

Accepted Answer

A) True 
 B)False

Question 16

If n = 15 and p = .4,then the standard deviation of the binomial distribution is:

Accepted Answer

A) 9 
B) 6 
C) 3.6 
D) 1.897 
E) .4 
A) 9 
B) 6 
C) 3.6 
D) 1.897 
E) .4

Question 17

A study conducted by a local university found that 25 percent of college freshmen support increased spending on environmental issues.If 6 college freshmen are randomly selected,find the probability that exactly 3 support increased spending on environmental issues.

Accepted Answer

A) .0330 
B) .1318 
C) .7844 
D) .9624 
A) .0330 
B) .1318 
C) .7844 
D) .9624

Question 18

If n = 20 and p = .4,then the mean of the binomial distribution is:

Accepted Answer

A) .4 
B) 4.8 
C) 8 
D) 12 
A) .4 
B) 4.8 
C) 8 
D) 12

Question 19

In the context of the hypergeometric distribution,r is

Accepted Answer

A) Sample size. 
B) The number of items in the population that are successes. 
C) The number of times items that are sampled without replacement. 
D) The number of items in the sample that are successes. 
A) Sample size. 
B) The number of items in the population that are successes. 
C) The number of times items that are sampled without replacement. 
D) The number of items in the sample that are successes.

Question 20

If x is a Poisson random variable with a mean of 10,what is the probability that x is greater than or equal to 2?

Accepted Answer

A) .9972 
B) .0028 
C) .9995 
D) .0005 
A) .9972 
B) .0028 
C) .9995 
D) .0005

X has the probability distribution: -2 -1 9 1 2 () .2 .2 .2 .2 .2 Compute the expected value of X.

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

For a discrete probability distribution,the value of p(x)for each value of x falls between -1 and 1.

The number of calls coming into a PBX follows a Poisson process with a mean of 120 calls per hour.What is the probability of no calls in a one-minute interval?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the P(X = 2).

When p = .5,the binomial distribution will _________ be symmetric.

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What is the probability that all 3 of your DVDs will last at least three years?

The random variable x has a hypergeometric distribution,and the population contains 12 items.If you wanted to find the number of defects in a random sample of 3 selected items when the population contains 5 defects,identify the N,n,and r.

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μ_x = .16,μ_y = .07,σ_x = .11,σ_y = .11,and σ_xy² = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.

If x is a binomial random variable,then the standard deviation of x is given by:

Consider a Poisson distribution with an average of 3 customers per minute at the local grocery store.If X = the number of arrivals per minute,find the expected value of X.

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μ_x = .16,μ_y = .07,σ_x = .11,σ_y = .11,and σ_xy² = .0321.Find the mean and standard deviation of the portfolio return: P = .45x + .55y.

Depending on the mean of the Poisson distribution,the distribution can either be very skewed to the right or quite symmetrical.

If n = 15 and p = .4,then the standard deviation of the binomial distribution is:

A study conducted by a local university found that 25 percent of college freshmen support increased spending on environmental issues.If 6 college freshmen are randomly selected,find the probability that exactly 3 support increased spending on environmental issues.

If n = 20 and p = .4,then the mean of the binomial distribution is:

In the context of the hypergeometric distribution,r is

If x is a Poisson random variable with a mean of 10,what is the probability that x is greater than or equal to 2?

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

X has the probability distribution: -2 -1 9 1 2 () .2 .2 .2 .2 .2 Compute the expected value of X.

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

For a discrete probability distribution,the value of p(x)for each value of x falls between -1 and 1.

The number of calls coming into a PBX follows a Poisson process with a mean of 120 calls per hour.What is the probability of no calls in a one-minute interval?

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the P(X = 2).

When p = .5,the binomial distribution will _________ be symmetric.

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What is the probability that all 3 of your DVDs will last at least three years?

The random variable x has a hypergeometric distribution,and the population contains 12 items.If you wanted to find the number of defects in a random sample of 3 selected items when the population contains 5 defects,identify the N,n,and r.

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μx = .16,μy = .07,σx = .11,σy = .11,and σxy2 = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.

If x is a binomial random variable,then the standard deviation of x is given by:

Consider a Poisson distribution with an average of 3 customers per minute at the local grocery store.If X = the number of arrivals per minute,find the expected value of X.

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μx = .16,μy = .07,σx = .11,σy = .11,and σxy2 = .0321.Find the mean and standard deviation of the portfolio return: P = .45x + .55y.

Depending on the mean of the Poisson distribution,the distribution can either be very skewed to the right or quite symmetrical.

If n = 15 and p = .4,then the standard deviation of the binomial distribution is:

A study conducted by a local university found that 25 percent of college freshmen support increased spending on environmental issues.If 6 college freshmen are randomly selected,find the probability that exactly 3 support increased spending on environmental issues.

If n = 20 and p = .4,then the mean of the binomial distribution is:

In the context of the hypergeometric distribution,r is

If x is a Poisson random variable with a mean of 10,what is the probability that x is greater than or equal to 2?

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

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μ_x = .16,μ_y = .07,σ_x = .11,σ_y = .11,and σ_xy² = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μ_x = .16,μ_y = .07,σ_x = .11,σ_y = .11,and σ_xy² = .0321.Find the mean and standard deviation of the portfolio return: P = .45x + .55y.