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 
D) A,B,or C above dependent on the value of the mean 
E) A,B,or C above dependent on the value of the standard deviation 
A) Less than 
B) Greater than 
C) Equal to 
D) A,B,or C above dependent on the value of the mean 
E) A,B,or C above dependent on the value of the standard deviation

Question 2

Find z when the area to the left of z is .05

Accepted Answer

A) 1.645 
B) 1.00 
C) -1.645 
D) -1.96 
A) 1.645 
B) 1.00 
C) -1.645 
D) -1.96

Question 3

Suppose that the waiting time for a license plate renewal at a local office of a state motor vehicle department has been found to be normally distributed with a mean of 30 minutes and a standard deviation of 8 minutes.What is the probability that a randomly selected individual will have a waiting time no more than 22 minutes?

Accepted Answer

A) .1587 
B) .9977 
C) .8413 
D) .0023 
A) .1587 
B) .9977 
C) .8413 
D) .0023

Question 4

Which of the following is a continuous distribution?

Accepted Answer

A) Poisson 
B) Hypergeometric 
C) Exponential 
D) Binomial 
A) Poisson 
B) Hypergeometric 
C) Exponential 
D) Binomial

Question 5

The weight of a product is normally distributed with a mean of four ounces and a variance of .25 "squared ounces." What is the probability that a randomly selected unit from a recently manufactured batch weighs more than 3.75 ounces?

Accepted Answer

A) .3085 
B) .6915 
C) .1587 
D) .8413 
A) .3085 
B) .6915 
C) .1587 
D) .8413

Question 6

The weight of a product is normally distributed with a mean 5 ounces.A randomly selected unit of this product weighs 7.1 ounces.The probability of a unit weighing more than 7.1 ounces is .0014.The production supervisor has lost files containing various pieces of information regarding this process including the standard deviation.Determine the value of standard deviation for this process.

Accepted Answer

A) 1.67 
B) 0.70 
C) 2.10 
D) 0.50 
A) 1.67 
B) 0.70 
C) 2.10 
D) 0.50

Question 7

The mean life of pair of shoes is 40 months with a standard deviation of 8 months.If the life of the shoes is normally distributed,how many pairs of shoes out of one million will need replacement before 36 months?

Accepted Answer

A) 500,000 
B) 808,500 
C) 191,500 
D) 308,500 
A) 500,000 
B) 808,500 
C) 191,500 
D) 308,500

Question 8

What is the probability that a random variable having a standard normal distribution is between .87 and 1.28?

Accepted Answer

A) .0919 
B) .4100 
C) .6517 
D) .3483 
A) .0919 
B) .4100 
C) .6517 
D) .3483

Question 9

Consider a normal population with a mean of 10 and a variance of 4.Find P(X < 6).

Accepted Answer

A) .0228 
B) .1587 
C) .8413 
D) .9772 
A) .0228 
B) .1587 
C) .8413 
D) .9772

Question 10

Find z when the area between 0 and z is .4750

Accepted Answer

A) -1.96 
B) 1.96 
C) 0.68 
D) -0.68 
A) -1.96 
B) 1.96 
C) 0.68 
D) -0.68

Question 11

A student's grade on an examination was transformed to a z value which is negative.Therefore,we know that he scored:

Accepted Answer

A) Higher than 16% of the class 
B) Higher than 45% of the class 
C) Above the first quartile 
D) Below the mean 
E) Lower than 16% of the class 
A) Higher than 16% of the class 
B) Higher than 45% of the class 
C) Above the first quartile 
D) Below the mean 
E) Lower than 16% of the class

Question 12

Consider a normal population with a mean of 10 and a variance of 4.Find P(X $\ge$ 10).

Accepted Answer

A) 1.00 
B) 0.00 
C) 0.50 
D) -0.50 
A) 1.00 
B) 0.00 
C) 0.50 
D) -0.50

Question 13

The area under the curve of a valid continuous probability distribution must _____.

Accepted Answer

A) Equal 1 
B) Be between 0 and 1 
C) Be infinite 
D) Be less than 1 
A) Equal 1 
B) Be between 0 and 1 
C) Be infinite 
D) Be less than 1

Question 14

The MPG (Miles per Gallon)for a mid-size car is normally distributed with a mean of 32 and a standard deviation of .8.What is the probability that the MPG for a selected mid-size car would be: Less than 33.2?

Accepted Answer

A) 43.32% 
B) 6.68% 
C) 93.32% 
D) 86.64% 
E) 13.36% 
A) 43.32% 
B) 6.68% 
C) 93.32% 
D) 86.64% 
E) 13.36%

Question 15

In a statistical study,the random variable X = 1,if the house is colonial,and X = 0 if the house is not colonial,then it can be stated that the random variable is continuous.

Accepted Answer

A) True 
 B)False

Question 16

The average time a subscriber spends reading the local newspaper is 49 minutes.Assume the standard deviation is 16 minutes and that the times are normally distributed. What is the probability a subscriber will spend no more than 30 minutes reading the paper?

Accepted Answer

A) .1170 
B) .0301 
C) .8830 
D) .9699 
A) .1170 
B) .0301 
C) .8830 
D) .9699

Question 17

If the mileage per gallon for a car is normally distributed,32 mpg has a z-score of 1.2,and 24 mpg has a z-score of -.4,what is the mean mpg of the distribution?

Accepted Answer

A) 28 
B) 26 
C) 30 
D) 38 
A) 28 
B) 26 
C) 30 
D) 38

Question 18

An apple juice producer buys all his apples from a conglomerate of apple growers in one northwest state.The amount of juice squeezed from each of these apples is approximately normally distributed with a mean of 2.25 ounces and a standard deviation of 0.15 ounce. Between what two values (in ounces)symmetrically distributed around the population mean will 80% of the apples fall?

Accepted Answer

A) [2.13 2.37] 
B) [2.10 2.40] 
C) [2.06 2.44] 
D) [1.95 2.55] 
A) [2.13 2.37] 
B) [2.10 2.40] 
C) [2.06 2.44] 
D) [1.95 2.55]

Question 19

A standard normal distribution has a mean of _____ and standard deviation of _____.

Accepted Answer

A) zero,zero 
B) zero,one 
C) one,one 
D) one,zero 
A) zero,zero 
B) zero,one 
C) one,one 
D) one,zero

Question 20

While conducting experiments,a marine biologist selects water depths from a uniformly distributed collection that vary between 2.00 m and 7.00 m.What is the probability that a randomly selected depth is between 2.25 m and 5.00 m?

Accepted Answer

A) .79 
B) .45 
C) .55 
D) .50 
A) .79 
B) .45 
C) .55 
D) .50

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.

Find z when the area to the left of z is .05

Which of the following is a continuous distribution?

The weight of a product is normally distributed with a mean of four ounces and a variance of .25 "squared ounces." What is the probability that a randomly selected unit from a recently manufactured batch weighs more than 3.75 ounces?

The mean life of pair of shoes is 40 months with a standard deviation of 8 months.If the life of the shoes is normally distributed,how many pairs of shoes out of one million will need replacement before 36 months?

What is the probability that a random variable having a standard normal distribution is between .87 and 1.28?

Consider a normal population with a mean of 10 and a variance of 4.Find P(X < 6).

Find z when the area between 0 and z is .4750

A student's grade on an examination was transformed to a z value which is negative.Therefore,we know that he scored:

Consider a normal population with a mean of 10 and a variance of 4.Find P(X $\ge$ 10).

The area under the curve of a valid continuous probability distribution must _____.

The MPG (Miles per Gallon)for a mid-size car is normally distributed with a mean of 32 and a standard deviation of .8.What is the probability that the MPG for a selected mid-size car would be: Less than 33.2?

In a statistical study,the random variable X = 1,if the house is colonial,and X = 0 if the house is not colonial,then it can be stated that the random variable is continuous.

The average time a subscriber spends reading the local newspaper is 49 minutes.Assume the standard deviation is 16 minutes and that the times are normally distributed. What is the probability a subscriber will spend no more than 30 minutes reading the paper?

If the mileage per gallon for a car is normally distributed,32 mpg has a z-score of 1.2,and 24 mpg has a z-score of -.4,what is the mean mpg of the distribution?

A standard normal distribution has a mean of _ and standard deviation of _.

While conducting experiments,a marine biologist selects water depths from a uniformly distributed collection that vary between 2.00 m and 7.00 m.What is the probability that a randomly selected depth is between 2.25 m and 5.00 m?

An Introduction to Business Statistics

Descriptive Statistics: Tabular and Graphical Methods

Descriptive Statistics: Numerical Methods

Probability

Discrete Random Variables

Sampling and Sampling Distributions

Confidence Intervals

Hypothesis Testing

Statistical Inferences Based on Two Samples

Experimental Design and Analysis of Variance

Chi-Square Tests

Simple Linear Regression Analysis

Multiple Regression

Model Building and Model Diagnostics

Time Series Forecasting

Process Improvement Using Control Charts

Nonparametric Methods

Decision Theory

Filters

Exam 6: Continuous Random Variables

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.

Find z when the area to the left of z is .05

Which of the following is a continuous distribution?

The weight of a product is normally distributed with a mean of four ounces and a variance of .25 "squared ounces." What is the probability that a randomly selected unit from a recently manufactured batch weighs more than 3.75 ounces?

The mean life of pair of shoes is 40 months with a standard deviation of 8 months.If the life of the shoes is normally distributed,how many pairs of shoes out of one million will need replacement before 36 months?

What is the probability that a random variable having a standard normal distribution is between .87 and 1.28?

Consider a normal population with a mean of 10 and a variance of 4.Find P(X < 6).

Find z when the area between 0 and z is .4750

A student's grade on an examination was transformed to a z value which is negative.Therefore,we know that he scored:

Consider a normal population with a mean of 10 and a variance of 4.Find P(X ≥\ge≥ 10).

The area under the curve of a valid continuous probability distribution must _____.

The MPG (Miles per Gallon)for a mid-size car is normally distributed with a mean of 32 and a standard deviation of .8.What is the probability that the MPG for a selected mid-size car would be: Less than 33.2?

In a statistical study,the random variable X = 1,if the house is colonial,and X = 0 if the house is not colonial,then it can be stated that the random variable is continuous.

The average time a subscriber spends reading the local newspaper is 49 minutes.Assume the standard deviation is 16 minutes and that the times are normally distributed. What is the probability a subscriber will spend no more than 30 minutes reading the paper?

If the mileage per gallon for a car is normally distributed,32 mpg has a z-score of 1.2,and 24 mpg has a z-score of -.4,what is the mean mpg of the distribution?

A standard normal distribution has a mean of _____ and standard deviation of _____.

While conducting experiments,a marine biologist selects water depths from a uniformly distributed collection that vary between 2.00 m and 7.00 m.What is the probability that a randomly selected depth is between 2.25 m and 5.00 m?

An Introduction to Business Statistics

Descriptive Statistics: Tabular and Graphical Methods

Descriptive Statistics: Numerical Methods

Probability

Discrete Random Variables

Sampling and Sampling Distributions

Confidence Intervals

Hypothesis Testing

Statistical Inferences Based on Two Samples

Experimental Design and Analysis of Variance

Chi-Square Tests

Simple Linear Regression Analysis

Multiple Regression

Model Building and Model Diagnostics

Time Series Forecasting

Process Improvement Using Control Charts

Nonparametric Methods

Decision Theory

Filters

Consider a normal population with a mean of 10 and a variance of 4.Find P(X $\ge$ 10).

A standard normal distribution has a mean of _ and standard deviation of _.