Question 1

The expected value,E(X),of a binomial probability distribution with n trials and probability p of success is:

Accepted Answer

A) n + p 
B) np(1 − p) 
C) np 
D) n + p − 1

Question 2

Shopping Outlet
 A shopping outlet estimates the probability distribution of the number of stores shoppers actually enter as shown in the table below.  ​ ​
-{Shopping Outlet Narrative} Use the laws of expected value to calculate the mean of Y from the probability distribution of X.

Accepted Answer

The answer of  Shopping Outlet
 A shopping outlet estimates...

Question 3

Online Bankers 
An official from the securities commission estimates that 75% of all online bankers have profited from the use of insider information.Assume that 15 online bankers are selected at random from the commission's registry. ​ ​
-{Online Bankers Narrative} Find the variance and standard deviation of the number of Online bankers who have profited from the use of insider information.

Accepted Answer

The answer of Online Bankers 
An official from the securities...

Question 4

A remedial program evenly enrolls tradition and non-traditional students.If a random sample of 4 students is selected from the program to be interviewed about the introduction of a new on-line class,what is the probability that all 4 students selected are traditional students?

Accepted Answer

The answer of A remedial program evenly enrolls tradition and...

Question 5

Which of the following about the binomial distribution is not a true statement?

Accepted Answer

A) The probability of success must be constant from trial to trial. 
B) The random variable of interest is continuous. 
C) Each outcome may be classified as either "success" or "failure". 
D) Each outcome is independent of the other.

Question 6

Classified Department Phone Calls 
A classified department receives an average of 10 telephone calls each afternoon between 2 and 4 P.M.The calls occur randomly and independently of one another. ​ ​
-{Classified Department Phone Calls Narrative} Find the probability that the department will receive at least five calls between 2 and 4 P.M.on a particular afternoon.

Accepted Answer

The answer of Classified Department Phone Calls 
A classified department...

Question 7

The weighted average of the possible values that a random variable X can assume,where the weights are the probabilities of occurrence of those values,is referred to as the:

Accepted Answer

A) variance. 
B) standard deviation. 
C) expected value. 
D) None of these choices.

Question 8

Online Bankers 
An official from the securities commission estimates that 75% of all online bankers have profited from the use of insider information.Assume that 15 online bankers are selected at random from the commission's registry. ​ ​
-{Online Bankers Narrative} Find the probability that at most 10 have profited from insider information.

Accepted Answer

The answer of Online Bankers 
An official from the securities...

Question 9

The trials in a binomial experiment are ____________________,meaning the outcome of one trial does not affect the outcomes of any other trials.

Accepted Answer

The answer of The trials in a binomial experiment are...

Question 10

Katie's Portfolio 
​ Katie is given the following information about the returns on two stocks: E(RS1U1B11S1U1B0)= 0.10,E(RS1U1B12S1U1B0)= 0.15,V(RS1U1B11S1U1B0)= 0.0225,and V(RS1U1B12S1U1B0)= 0.0441. ​ ​
-{Katie's Portfolio Narrative} Compute the variance of the portfolio composed of 60% stock 1,and 40% stock 2,if the coefficient of correlation is 0.40.

Accepted Answer

The answer of  Katie's Portfolio 
​ Katie is given...

Question 11

Number of Horses ​
 The random variable X represents the number of horses per family in a rural area in Iowa,with the probability distribution: p(x)= 0.05x,x = 2,3,4,5,or 6. ​ ​
-{Number of Horses Narrative} Express the probability distribution in tabular form.

Accepted Answer

The answer of  Number of Horses ​
 The random...

Question 12

The monthly sales at a Gas Station have a mean of $50,000 and a standard deviation of $6,000.Profits are calculated by multiplying sales by 40% and subtracting fixed costs of $12,000.Find the mean and standard deviation of monthly profits.

Accepted Answer

The answer of The monthly sales at a Gas Station...

Question 13

Number of Hamsters 
The joint probability distribution of X and Y is shown in the accompanying table,where X denotes the number of hamsters that Quinn may have next year,and Y denotes the number of hamsters that her boyfriend,Jason,may have when she moves in with him next year.  ​ ​
-{Number of Hamsters Narrative} Determine the marginal probability distributions of X and Y.

Accepted Answer

The answer of  Number of Hamsters 
The joint probability...

Question 14

The possible values of a Poisson random variable start at ____________________.

Accepted Answer

The answer of The possible values of a Poisson random...

Question 15

In a(n)____________________ experiment,the probability of a success in an interval is the same for all equal-sized intervals.

Accepted Answer

The answer of In a(n)____________________ experiment,the probability of a success...

Question 16

Which of the following is not a required condition for the distribution of a discrete random variable X that can assume values xi?

Accepted Answer

A) 0 ≤ p(xi)≤ 1 for all xi 
B)   
C) p(xi)> 1 for all xi 
D) All of these choices are true.

Question 17

Number of Motorcycles 
The probability distribution of a discrete random variable X is shown below,where X represents the number of motorcycles owned by a family.  ​ ​
-{Number of Motorcycles Narrative} Apply the laws of expected value and variance to find the following:
a.V(3X)
b.V(3X − 2)
c.V(3)
d.V(3X)− 2

Accepted Answer

The answer of Number of Motorcycles 
The probability distribution of...

Question 18

Golfing Store 
The joint probability distribution of variables X and Y is shown in the table below,where X is the number of drivers and Y is the number of putters sold daily in a small golfing store.  ​ ​
-{Golfing Store Narrative} Calculate the expected values of X and Y.

Accepted Answer

The answer of Golfing Store 
The joint probability distribution of...

Question 19

The probability P(X ≤ x)is called a(n)____________________ probability.The binomial table reports these probabilities.

Accepted Answer

The answer of The probability P(X ≤ x)is called a(n)____________________...

Question 20

If X and Y are random variables with E(X)= 6 and E(Y)= 9,then E(2X + 3Y)is:

Accepted Answer

A) 39 
B) 15 
C) 27 
D) 12

Exam 7: Random Variables and Discrete Probability Distributions

The expected value,E(X) ,of a binomial probability distribution with n trials and probability p of success is:

Shopping Outlet A shopping outlet estimates the probability distribution of the number of stores shoppers actually enter as shown in the table below. -{Shopping Outlet Narrative} Use the laws of expected value to calculate the mean of Y from the probability distribution of X.

A remedial program evenly enrolls tradition and non-traditional students.If a random sample of 4 students is selected from the program to be interviewed about the introduction of a new on-line class,what is the probability that all 4 students selected are traditional students?

Which of the following about the binomial distribution is not a true statement?

The weighted average of the possible values that a random variable X can assume,where the weights are the probabilities of occurrence of those values,is referred to as the:

The trials in a binomial experiment are ____________________,meaning the outcome of one trial does not affect the outcomes of any other trials.

Number of Horses The random variable X represents the number of horses per family in a rural area in Iowa,with the probability distribution: p(x)= 0.05x,x = 2,3,4,5,or 6. -{Number of Horses Narrative} Express the probability distribution in tabular form.

The monthly sales at a Gas Station have a mean of $50,000 and a standard deviation of $6,000.Profits are calculated by multiplying sales by 40% and subtracting fixed costs of $12,000.Find the mean and standard deviation of monthly profits.

The possible values of a Poisson random variable start at ____________________.

In a(n)____________________ experiment,the probability of a success in an interval is the same for all equal-sized intervals.

Which of the following is not a required condition for the distribution of a discrete random variable X that can assume values x_i?

Golfing Store The joint probability distribution of variables X and Y is shown in the table below,where X is the number of drivers and Y is the number of putters sold daily in a small golfing store. -{Golfing Store Narrative} Calculate the expected values of X and Y.

The probability P(X ≤ x)is called a(n)____________________ probability.The binomial table reports these probabilities.

If X and Y are random variables with E(X) = 6 and E(Y) = 9,then E(2X + 3Y) is:

Exam 7: Random Variables and Discrete Probability Distributions

The expected value,E(X) ,of a binomial probability distribution with n trials and probability p of success is:

Shopping Outlet A shopping outlet estimates the probability distribution of the number of stores shoppers actually enter as shown in the table below. ​ ​ -{Shopping Outlet Narrative} Use the laws of expected value to calculate the mean of Y from the probability distribution of X.

A remedial program evenly enrolls tradition and non-traditional students.If a random sample of 4 students is selected from the program to be interviewed about the introduction of a new on-line class,what is the probability that all 4 students selected are traditional students?

Which of the following about the binomial distribution is not a true statement?

The weighted average of the possible values that a random variable X can assume,where the weights are the probabilities of occurrence of those values,is referred to as the:

The trials in a binomial experiment are ____________________,meaning the outcome of one trial does not affect the outcomes of any other trials.

Number of Horses ​ The random variable X represents the number of horses per family in a rural area in Iowa,with the probability distribution: p(x)= 0.05x,x = 2,3,4,5,or 6. ​ ​ -{Number of Horses Narrative} Express the probability distribution in tabular form.

The monthly sales at a Gas Station have a mean of $50,000 and a standard deviation of $6,000.Profits are calculated by multiplying sales by 40% and subtracting fixed costs of $12,000.Find the mean and standard deviation of monthly profits.

The possible values of a Poisson random variable start at ____________________.

In a(n)____________________ experiment,the probability of a success in an interval is the same for all equal-sized intervals.

Which of the following is not a required condition for the distribution of a discrete random variable X that can assume values xi?

Golfing Store The joint probability distribution of variables X and Y is shown in the table below,where X is the number of drivers and Y is the number of putters sold daily in a small golfing store. ​ ​ -{Golfing Store Narrative} Calculate the expected values of X and Y.

The probability P(X ≤ x)is called a(n)____________________ probability.The binomial table reports these probabilities.

If X and Y are random variables with E(X) = 6 and E(Y) = 9,then E(2X + 3Y) is:

Shopping Outlet A shopping outlet estimates the probability distribution of the number of stores shoppers actually enter as shown in the table below. -{Shopping Outlet Narrative} Use the laws of expected value to calculate the mean of Y from the probability distribution of X.

Number of Horses The random variable X represents the number of horses per family in a rural area in Iowa,with the probability distribution: p(x)= 0.05x,x = 2,3,4,5,or 6. -{Number of Horses Narrative} Express the probability distribution in tabular form.

Which of the following is not a required condition for the distribution of a discrete random variable X that can assume values x_i?

Golfing Store The joint probability distribution of variables X and Y is shown in the table below,where X is the number of drivers and Y is the number of putters sold daily in a small golfing store. -{Golfing Store Narrative} Calculate the expected values of X and Y.