Question 1

The area under the normal curve between z = 0 and z = 1 is ______________ the area under the normal curve between z = 1 and z = 2.

Accepted Answer

A)  less than 
B)  greater than 
C)  equal to 
A)  less than 
B)  greater than 
C)  equal to

Question 2

The standard deviation of a normal random variable X is $20.Given that P(X ≤ $10)= 0.1841.From this we can determine that the mean of the distribution is equal to:

Accepted Answer

A)  $13. 
B)  $26. 
C)  $20. 
D)  $28. 
A)  $13. 
B)  $26. 
C)  $20. 
D)  $28.

Question 3

The normal is a good approximation to the binomial when n is greater than or equal to 10.

Accepted Answer

A) True 
 B)False

Question 4

If the random variable Z has a standard normal distribution,then P(1.25 ≤ Z ≤ 2.17)is:

Accepted Answer

A)  0.0906. 
B)  0.9200. 
C)  0.4700. 
D)  0.3944. 
A)  0.0906. 
B)  0.9200. 
C)  0.4700. 
D)  0.3944.

Question 5

The true proportion of accounts receivable with some kind of error is 4 percent for Venal Enterprises.If an auditor randomly samples 50 accounts receivable,it is acceptable to use the normal approximation to estimate the probability that fewer than two will contain errors.

Accepted Answer

A) True 
 B)False

Question 6

If the random variable Z has a standard normal distribution,then P(Z ≤ -1.37)is:

Accepted Answer

A)  0.9147. 
B)  0.4147. 
C)  0.5016. 
D)  0.0853. 
A)  0.9147. 
B)  0.4147. 
C)  0.5016. 
D)  0.0853.

Question 7

In a continuous distribution:

Accepted Answer

A)  P(X < 5)is the same as P(X ≤ 5). 
B)  P(X < 5)is less than P(X ≤ 5). 
C)  P(X < 5)is more than P(X ≤ 5). 
A)  P(X < 5)is the same as P(X ≤ 5). 
B)  P(X < 5)is less than P(X ≤ 5). 
C)  P(X < 5)is more than P(X ≤ 5).

Question 8

Any two normal curves are the same except for their:

Accepted Answer

A)  standard deviations. 
B)  means. 
C)  standard deviations and means. 
D)  standard deviations,means,skewness,and kurtosis. 
A)  standard deviations. 
B)  means. 
C)  standard deviations and means. 
D)  standard deviations,means,skewness,and kurtosis.

Question 9

The normal distribution is a good approximation to the binomial if n = 200 and π = .03.

Accepted Answer

A) True 
 B)False

Question 10

The probability is .80 that a standard normal random variable is between -z and +z.The value of z is approximately:

Accepted Answer

A)  1.28. 
B)  1.35. 
C)  1.96. 
D)  1.45. 
A)  1.28. 
B)  1.35. 
C)  1.96. 
D)  1.45.

Question 11

The normal distribution is a good approximation to the binomial if n = 25 and π = .50.

Accepted Answer

A) True 
 B)False

Question 12

Which statement is incorrect?

Accepted Answer

A)  The triangular distribution always has a single mode. 
B)  The mean of the triangular distribution is (a + b + c)/3. 
C)  The triangular distribution is right-skewed. 
A)  The triangular distribution always has a single mode. 
B)  The mean of the triangular distribution is (a + b + c)/3. 
C)  The triangular distribution is right-skewed.

Question 13

If arrivals occur at a mean rate of 1.6 events per minute,the exponential probability of waiting less than 1 minute for the next arrival is:

Accepted Answer

A)  .2019. 
B)  .7104. 
C)  .8812. 
D)  .7981. 
A)  .2019. 
B)  .7104. 
C)  .8812. 
D)  .7981.

Question 14

A letter is mailed to a sample of 500 homeowners.Based on past experience,the probability of an undeliverable letter is 0.06.The normal approximation to the binomial probability of 40 or more undeliverable letters is:

Accepted Answer

A)  0.9632 
B)  0.0368 
C)  0.2305 
D)  0.7695 
A)  0.9632 
B)  0.0368 
C)  0.2305 
D)  0.7695

Question 15

A machine dispenses water into a glass.Assuming that the amount of water dispensed follows a continuous uniform distribution from 10 ounces to 16 ounces,what is the probability that 13 or more ounces will be dispensed in a given glass?

Accepted Answer

A)  .1666 
B)  .3333 
C)  .5000 
D)  .6666 
A)  .1666 
B)  .3333 
C)  .5000 
D)  .6666

Question 16

Bob used a triangular distribution of T(20,30,61)to represent his daily commute time (minutes).Which statement is incorrect?

Accepted Answer

A)  The distribution is right-skewed. 
B)  The mode of the distribution exceeds the mean. 
C)  The mean of the distribution is 37. 
D)  The midrange of the distribution is 40.5. 
A)  The distribution is right-skewed. 
B)  The mode of the distribution exceeds the mean. 
C)  The mean of the distribution is 37. 
D)  The midrange of the distribution is 40.5.

Question 17

The triangular distribution is symmetric.

Accepted Answer

A) True 
 B)False

Question 18

Excel's =RAND()function produces random numbers that are uniformly distributed from 0 to 1.What is the probability that the random number exceeds .75?

Accepted Answer

A)  75 percent 
B)  50 percent 
C)  25 percent 
A)  75 percent 
B)  50 percent 
C)  25 percent

Question 19

A random variable X is best described by a continuous uniform distribution from 20 to 45 inclusive.The standard deviation of this distribution is approximately:

Accepted Answer

A)  52.1. 
B)  32.5. 
C)  6.85. 
D)  7.22. 
A)  52.1. 
B)  32.5. 
C)  6.85. 
D)  7.22.

Question 20

A certain assembly line at Vexing Manufacturing Company averages 30 minutes between breakdowns.What is the probability that less than 6 minutes will elapse before the next breakdown?

Accepted Answer

A)  .8187 
B)  .0488 
C)  .1813 
D)  .2224 
A)  .8187 
B)  .0488 
C)  .1813 
D)  .2224

The area under the normal curve between z = 0 and z = 1 is ______________ the area under the normal curve between z = 1 and z = 2.

The standard deviation of a normal random variable X is $20.Given that P(X ≤ $10)= 0.1841.From this we can determine that the mean of the distribution is equal to:

The normal is a good approximation to the binomial when n is greater than or equal to 10.

If the random variable Z has a standard normal distribution,then P(1.25 ≤ Z ≤ 2.17)is:

The true proportion of accounts receivable with some kind of error is 4 percent for Venal Enterprises.If an auditor randomly samples 50 accounts receivable,it is acceptable to use the normal approximation to estimate the probability that fewer than two will contain errors.

If the random variable Z has a standard normal distribution,then P(Z ≤ -1.37)is:

In a continuous distribution:

Any two normal curves are the same except for their:

The normal distribution is a good approximation to the binomial if n = 200 and π = .03.

The probability is .80 that a standard normal random variable is between -z and +z.The value of z is approximately:

The normal distribution is a good approximation to the binomial if n = 25 and π = .50.

Which statement is incorrect?

If arrivals occur at a mean rate of 1.6 events per minute,the exponential probability of waiting less than 1 minute for the next arrival is:

A letter is mailed to a sample of 500 homeowners.Based on past experience,the probability of an undeliverable letter is 0.06.The normal approximation to the binomial probability of 40 or more undeliverable letters is:

A machine dispenses water into a glass.Assuming that the amount of water dispensed follows a continuous uniform distribution from 10 ounces to 16 ounces,what is the probability that 13 or more ounces will be dispensed in a given glass?

Bob used a triangular distribution of T(20,30,61)to represent his daily commute time (minutes).Which statement is incorrect?

The triangular distribution is symmetric.

Excel's =RAND()function produces random numbers that are uniformly distributed from 0 to 1.What is the probability that the random number exceeds .75?

A random variable X is best described by a continuous uniform distribution from 20 to 45 inclusive.The standard deviation of this distribution is approximately:

A certain assembly line at Vexing Manufacturing Company averages 30 minutes between breakdowns.What is the probability that less than 6 minutes will elapse before the next breakdown?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time-Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters

Exam 7: Continuous Probability Distributions

The area under the normal curve between z = 0 and z = 1 is ______________ the area under the normal curve between z = 1 and z = 2.

The standard deviation of a normal random variable X is $20.Given that P(X ≤ $10)= 0.1841.From this we can determine that the mean of the distribution is equal to:

The normal is a good approximation to the binomial when n is greater than or equal to 10.

If the random variable Z has a standard normal distribution,then P(1.25 ≤ Z ≤ 2.17)is:

The true proportion of accounts receivable with some kind of error is 4 percent for Venal Enterprises.If an auditor randomly samples 50 accounts receivable,it is acceptable to use the normal approximation to estimate the probability that fewer than two will contain errors.

If the random variable Z has a standard normal distribution,then P(Z ≤ -1.37)is:

In a continuous distribution:

Any two normal curves are the same except for their:

The normal distribution is a good approximation to the binomial if n = 200 and π = .03.

The probability is .80 that a standard normal random variable is between -z and +z.The value of z is approximately:

The normal distribution is a good approximation to the binomial if n = 25 and π = .50.

Which statement is incorrect?

If arrivals occur at a mean rate of 1.6 events per minute,the exponential probability of waiting less than 1 minute for the next arrival is:

A letter is mailed to a sample of 500 homeowners.Based on past experience,the probability of an undeliverable letter is 0.06.The normal approximation to the binomial probability of 40 or more undeliverable letters is:

A machine dispenses water into a glass.Assuming that the amount of water dispensed follows a continuous uniform distribution from 10 ounces to 16 ounces,what is the probability that 13 or more ounces will be dispensed in a given glass?

Bob used a triangular distribution of T(20,30,61)to represent his daily commute time (minutes).Which statement is incorrect?

The triangular distribution is symmetric.

Excel's =RAND()function produces random numbers that are uniformly distributed from 0 to 1.What is the probability that the random number exceeds .75?

A random variable X is best described by a continuous uniform distribution from 20 to 45 inclusive.The standard deviation of this distribution is approximately:

A certain assembly line at Vexing Manufacturing Company averages 30 minutes between breakdowns.What is the probability that less than 6 minutes will elapse before the next breakdown?

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Simple Regression

Multiple Regression

Time-Series Analysis

Chi-Square Tests

Nonparametric Tests

Quality Management

Filters