Question 1

If the probability distribution of X is $\begin{array} { c c } 
\mathrm { X } & \mathrm { P } ( \mathrm { X } ) \
3 & 1 / 8 \
4 & 1 / 8 \
5 & 3 / 8 \
6 & 3 / 8
\end{array}$
What is the expected value of X?

Accepted Answer

A) 1.0 
B) 5.0 
C) 2.25 
D) 2.24 
A) 1.0 
B) 5.0 
C) 2.25 
D) 2.24

Question 2

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 exactly three of the individuals have group A blood.

Accepted Answer

A) .4000 
B) .2765 
C) .5875 
D) .0041 
A) .4000 
B) .2765 
C) .5875 
D) .0041

Question 3

Which of the following is a valid probability value for a discrete random variable?

Accepted Answer

A) .2 
B) 1.01 
C) -.7 
D) All of these 
A) .2 
B) 1.01 
C) -.7 
D) All of these

Question 4

A fair die is rolled 10 times.What is the probability that an even number (2,4,or 6)will occur between 2 and 4 times?

Accepted Answer

A) .6123 
B) .1709 
C) .1611 
D) .3662 
E) .3223 
A) .6123 
B) .1709 
C) .1611 
D) .3662 
E) .3223

Question 5

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 variance value of X.

Accepted Answer

A) 1.58 
B) .955 
C) .912 
D) .625 
A) 1.58 
B) .955 
C) .912 
D) .625

Question 6

With two random variables x and y,a positive covariance says that as x increases,y tends to increase in a linear fashion.

Accepted Answer

A) True 
 B)False

Question 7

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 all five will be repaired on the same day?

Accepted Answer

A) .0010 
B) .6328 
C) .9990 
D) .2373 
A) .0010 
B) .6328 
C) .9990 
D) .2373

Question 8

A random variable is said to be discrete if

Accepted Answer

A) Its outcomes are countable. 
B) It can assume any real number within a given interval. 
C) The rules of probability apply. 
D) It can be represented graphically. 
A) Its outcomes are countable. 
B) It can assume any real number within a given interval. 
C) The rules of probability apply. 
D) It can be represented graphically.

Question 9

A random variable:

Accepted Answer

A) Is the result of a measurement. 
B) Can only be discrete. 
C) Can be thought of as representing an uncertain numerical outcome to an experiment. 
D) Is a binomial,Poisson,or hypergeometric variable. 
A) Is the result of a measurement. 
B) Can only be discrete. 
C) Can be thought of as representing an uncertain numerical outcome to an experiment. 
D) Is a binomial,Poisson,or hypergeometric variable.

Question 10

If x is a Poisson random variable with a mean of 10,what is the probability that x is greater than 6?

Accepted Answer

A) .9329 
B) .7797 
C) .8698 
D) .0002 
A) .9329 
B) .7797 
C) .8698 
D) .0002

Question 11

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 variance 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 12

The equation for the variance of the binomial distribution is given by:

Accepted Answer

A) px(1 - p)n-x 
B) np 
C) np(1 - p) 
D)  $\sqrt { n p ( 1 - p ) }$ 
A) px(1 - p)n-x 
B) np 
C) np(1 - p) 
D)  $\sqrt { n p ( 1 - p ) }$

Question 13

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.When there are 8 local letters mailed,what is the probability that the number delivered will be within 2 standard deviations of the mean?

Accepted Answer

A) .9950 
B) .9619 
C) .8131 
D) .9996 
A) .9950 
B) .9619 
C) .8131 
D) .9996

Question 14

A fair die is rolled 36 times.What is the standard deviation of the even number (2,4,or 6)outcomes?

Accepted Answer

A) 18 
B) 9 
C) 5 
D) 3 
E) 1.732 
A) 18 
B) 9 
C) 5 
D) 3 
E) 1.732

Question 15

A large disaster cleaning company estimates that 30 percent of the jobs it bids on are finished within the bid time.Looking at a random sample of 8 jobs that it has contracted,calculate the mean number of jobs completed within the bid time.

Accepted Answer

A) 4.0 
B) 2.4 
C) 2.0 
D) 5.6 
A) 4.0 
B) 2.4 
C) 2.0 
D) 5.6

Question 16

Historical data for a local steel manufacturing company show that the average number of defects per standard sheet of steel is 2.In addition,the number of defects per unit is distributed according to a Poisson distribution.A batch has just been completed.What is the probability that the first three units manufactured in this batch will contain at least a total of 4 defects?

Accepted Answer

A) .8488 
B) .7149 
C) .1512 
D) .2851 
A) .8488 
B) .7149 
C) .1512 
D) .2851

Question 17

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 standard deviation 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 18

For a random variable X,the mean value of the squared deviations of its values from their expected value is called its ____________.

Accepted Answer

A) Standard deviation 
B) Mean 
C) Probability 
D) Variance 
A) Standard deviation 
B) Mean 
C) Probability 
D) Variance

Question 19

The binomial distribution is characterized by situations that are analogous to

Accepted Answer

A) Drawing balls from an urn. 
B) Coin tossing. 
C) Counting defects on an item. 
D) Measuring the length of an item. 
A) Drawing balls from an urn. 
B) Coin tossing. 
C) Counting defects on an item. 
D) Measuring the length of an item.

Question 20

The mean of the binomial distribution is equal to:

Accepted Answer

A) p 
B) np 
C) px(1 - p)n-x 
D) (n)(p)(1 - p) 
E)  $\sqrt { n \cdot p ( 1 - p ) }$ 
A) p 
B) np 
C) px(1 - p)n-x 
D) (n)(p)(1 - p) 
E)  $\sqrt { n \cdot p ( 1 - p ) }$

If the probability distribution of X is () 3 1/8 4 1/8 5 3/8 6 3/8 What is the expected value of X?

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 exactly three of the individuals have group A blood.

Which of the following is a valid probability value for a discrete random variable?

A fair die is rolled 10 times.What is the probability that an even number (2,4,or 6)will occur between 2 and 4 times?

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

With two random variables x and y,a positive covariance says that as x increases,y tends to increase in a linear fashion.

A random variable is said to be discrete if

A random variable:

If x is a Poisson random variable with a mean of 10,what is the probability that x is greater than 6?

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 variance of X.

The equation for the variance of the binomial distribution is given by:

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.When there are 8 local letters mailed,what is the probability that the number delivered will be within 2 standard deviations of the mean?

A fair die is rolled 36 times.What is the standard deviation of the even number (2,4,or 6)outcomes?

A large disaster cleaning company estimates that 30 percent of the jobs it bids on are finished within the bid time.Looking at a random sample of 8 jobs that it has contracted,calculate the mean number of jobs completed within the bid time.

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 standard deviation for this distribution?

For a random variable X,the mean value of the squared deviations of its values from their expected value is called its ____________.

The binomial distribution is characterized by situations that are analogous to

The mean of the binomial distribution is equal to:

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

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Exam 5: Discrete Random Variables

If the probability distribution of X is () 3 1/8 4 1/8 5 3/8 6 3/8 What is the expected value of X?

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 exactly three of the individuals have group A blood.

Which of the following is a valid probability value for a discrete random variable?

A fair die is rolled 10 times.What is the probability that an even number (2,4,or 6)will occur between 2 and 4 times?

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

With two random variables x and y,a positive covariance says that as x increases,y tends to increase in a linear fashion.

A random variable is said to be discrete if

A random variable:

If x is a Poisson random variable with a mean of 10,what is the probability that x is greater than 6?

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 variance of X.

The equation for the variance of the binomial distribution is given by:

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.When there are 8 local letters mailed,what is the probability that the number delivered will be within 2 standard deviations of the mean?

A fair die is rolled 36 times.What is the standard deviation of the even number (2,4,or 6)outcomes?

A large disaster cleaning company estimates that 30 percent of the jobs it bids on are finished within the bid time.Looking at a random sample of 8 jobs that it has contracted,calculate the mean number of jobs completed within the bid time.

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 standard deviation for this distribution?

For a random variable X,the mean value of the squared deviations of its values from their expected value is called its ____________.

The binomial distribution is characterized by situations that are analogous to

The mean of the binomial distribution is equal to:

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