Question 1

What is the probability that a standard normal random variable will be between -2 and 2?

Accepted Answer

A) .4772 
B) .0228 
C) .9772 
D) .9544 
A) .4772 
B) .0228 
C) .9772 
D) .9544

Question 2

The mean life of a 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 3

A plant manager knows that the number of boxes of supplies received weekly is normally distributed with a mean of 200 and a standard deviation of 20.What percentage of the time will the number of boxes received weekly be greater than 210 or less than 180?

Accepted Answer

A) 69.15% 
B) 46.72% 
C) 19.15% 
D) 15.87% 
A) 69.15% 
B) 46.72% 
C) 19.15% 
D) 15.87%

Question 4

The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.2 inches.What is the probability that a sheet selected at random from the population is between 30.25 and 30.65 inches long?

Accepted Answer

A) .9987 
B) .1574 
C) .1587 
D) .8413 
A) .9987 
B) .1574 
C) .1587 
D) .8413

Question 5

An apple juice producer buys all his apples from a conglomerate of apple growers in one northwestern 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.What is the probability that a randomly selected apple will contain between 2.00 and 3.00 ounces?

Accepted Answer

A) .0475 
B) .4525 
C) .9525 
D) .9554 
A) .0475 
B) .4525 
C) .9525 
D) .9554

Question 6

The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910 grams and a standard deviation of 5 grams.We calculated the value of z for a specific box of this brand of cereal,and the z value was negative.This negative z value indicates that:

Accepted Answer

A) We made a mistake in our calculations,as z must always be a nonnegative number. 
B) The fill weight exceeds 910 grams. 
C) The fill weight is less than 910 grams. 
D) The fill weight is equal to 910 grams. 
E) The fill weight may be more or less than 910 grams depending on the value of the standard deviation. 
A) We made a mistake in our calculations,as z must always be a nonnegative number. 
B) The fill weight exceeds 910 grams. 
C) The fill weight is less than 910 grams. 
D) The fill weight is equal to 910 grams. 
E) The fill weight may be more or less than 910 grams depending on the value of the standard deviation.

Question 7

During the past six months,73.2 percent of US households purchased sugar.Assume that these expenditures are approximately normally distributed with a mean of $8.22 and a standard deviation of $1.10.Find the probability that a household spent more than $10.00 on sugar.

Accepted Answer

A) .7320 
B) .9474 
C) .0526 
D) .2680 
A) .7320 
B) .9474 
C) .0526 
D) .2680

Question 8

Values of the standard normal random variable are measured:

Accepted Answer

A) With reference to specific units. 
B) In the units in which the mean is measured. 
C) In the number of standard deviations from the mean. 
D) In squared units in which the mean is measured. 
E) None of these. 
A) With reference to specific units. 
B) In the units in which the mean is measured. 
C) In the number of standard deviations from the mean. 
D) In squared units in which the mean is measured. 
E) None of these.

Question 9

The z value tells us the number of ____________ that a value of x is from the mean.

Accepted Answer

A) Variances 
B) Standard deviations 
C) Medians 
D) Standard means 
A) Variances 
B) Standard deviations 
C) Medians 
D) Standard means

Question 10

A set of final examination grades in a calculus course was found to be normally distributed with a mean of 69 and a standard deviation of 9.What percentage of students scored between 65 and 89?

Accepted Answer

A) 65.68% 
B) 100% 
C) 98.68% 
D) 33.00% 
A) 65.68% 
B) 100% 
C) 98.68% 
D) 33.00%

Question 11

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 between 15 and 45 minutes?

Accepted Answer

A) 1.00 
B) .9699 
C) .5000 
D) .9398 
A) 1.00 
B) .9699 
C) .5000 
D) .9398

Question 12

It is appropriate to use the uniform distribution to describe a continuous random variable x when:

Accepted Answer

A) The area under the probability curve = 1. 
B) The probability curve f(x)> 0. 
C) The shape of the histogram of all possible values of x is nonsymmetrical. 
D) Relative frequencies of all possible values of x are about the same. 
A) The area under the probability curve = 1. 
B) The probability curve f(x)> 0. 
C) The shape of the histogram of all possible values of x is nonsymmetrical. 
D) Relative frequencies of all possible values of x are about the same.

Question 13

The binomial random variable x consists of n = 60 trials and has the probability of failure q = 0.4.Using the normal approximation,compute the probability of 45 successes.

Accepted Answer

The answer of The binomial random variable x consists of...

Question 14

The mean of a standard normal distribution is always equal to ____________.

Accepted Answer

A) 1 
B) 0.5 
C) 0 
D) -1 
A) 1 
B) 0.5 
C) 0 
D) -1

Question 15

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 16

The time between breakdowns of an alarm system is exponentially distributed with mean 10 days.What is the probability that there are no breakdowns on a given day?

Accepted Answer

A) .9048 
B) .3679 
C) .0952 
D) 0.000 
A) .9048 
B) .3679 
C) .0952 
D) 0.000

Question 17

When a ____________ probability distribution is used to approximate a ____________ probability distribution,we must make a ____________ correction.

Accepted Answer

A) Continuous,discrete,continuity 
B) Discrete,continuous,continuity 
C) Continuous,discrete,finite population 
D) None of these 
A) Continuous,discrete,continuity 
B) Discrete,continuous,continuity 
C) Continuous,discrete,finite population 
D) None of these

Question 18

The number of standard deviations that a value x is from the mean is a(n)____________.

Accepted Answer

A) Variance 
B) Exponential value 
C) z score 
D) Area 
A) Variance 
B) Exponential value 
C) z score 
D) Area

Question 19

The cashier service time at the local branch of the Rivertown bank has an exponential distribution with a mean of 2.5 minutes.What is the probability that the service time exceeds 3 minutes?

Accepted Answer

A) .3012 
B) .6988 
C) .4346 
D) .5654 
E) .0821 
A) .3012 
B) .6988 
C) .4346 
D) .5654 
E) .0821

Question 20

For a continuous random variable x,the height of the probability curve f(x)at a particular point indicates the value of the probability for that value.

Accepted Answer

A) True 
 B)False

What is the probability that a standard normal random variable will be between -2 and 2?

The mean life of a 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?

A plant manager knows that the number of boxes of supplies received weekly is normally distributed with a mean of 200 and a standard deviation of 20.What percentage of the time will the number of boxes received weekly be greater than 210 or less than 180?

The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.2 inches.What is the probability that a sheet selected at random from the population is between 30.25 and 30.65 inches long?

The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910 grams and a standard deviation of 5 grams.We calculated the value of z for a specific box of this brand of cereal,and the z value was negative.This negative z value indicates that:

During the past six months,73.2 percent of US households purchased sugar.Assume that these expenditures are approximately normally distributed with a mean of $8.22 and a standard deviation of $1.10.Find the probability that a household spent more than $10.00 on sugar.

Values of the standard normal random variable are measured:

The z value tells us the number of ____________ that a value of x is from the mean.

A set of final examination grades in a calculus course was found to be normally distributed with a mean of 69 and a standard deviation of 9.What percentage of students scored between 65 and 89?

It is appropriate to use the uniform distribution to describe a continuous random variable x when:

The binomial random variable x consists of n = 60 trials and has the probability of failure q = 0.4.Using the normal approximation,compute the probability of 45 successes.

The mean of a standard normal distribution is always equal to ____________.

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

The time between breakdowns of an alarm system is exponentially distributed with mean 10 days.What is the probability that there are no breakdowns on a given day?

When a probability distribution is used to approximate a probability distribution,we must make a correction.

The number of standard deviations that a value x is from the mean is a(n)____________.

The cashier service time at the local branch of the Rivertown bank has an exponential distribution with a mean of 2.5 minutes.What is the probability that the service time exceeds 3 minutes?

For a continuous random variable x,the height of the probability curve f(x)at a particular point indicates the value of the probability for that value.

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 and Model Building

Process Improvement Using Control Charts

Filters

Exam 6: Continuous Random Variables

What is the probability that a standard normal random variable will be between -2 and 2?

The mean life of a 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?

A plant manager knows that the number of boxes of supplies received weekly is normally distributed with a mean of 200 and a standard deviation of 20.What percentage of the time will the number of boxes received weekly be greater than 210 or less than 180?

The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.2 inches.What is the probability that a sheet selected at random from the population is between 30.25 and 30.65 inches long?

The fill weight of a certain brand of adult cereal is normally distributed with a mean of 910 grams and a standard deviation of 5 grams.We calculated the value of z for a specific box of this brand of cereal,and the z value was negative.This negative z value indicates that:

During the past six months,73.2 percent of US households purchased sugar.Assume that these expenditures are approximately normally distributed with a mean of $8.22 and a standard deviation of $1.10.Find the probability that a household spent more than $10.00 on sugar.

Values of the standard normal random variable are measured:

The z value tells us the number of ____________ that a value of x is from the mean.

A set of final examination grades in a calculus course was found to be normally distributed with a mean of 69 and a standard deviation of 9.What percentage of students scored between 65 and 89?

It is appropriate to use the uniform distribution to describe a continuous random variable x when:

The binomial random variable x consists of n = 60 trials and has the probability of failure q = 0.4.Using the normal approximation,compute the probability of 45 successes.

The mean of a standard normal distribution is always equal to ____________.

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

The time between breakdowns of an alarm system is exponentially distributed with mean 10 days.What is the probability that there are no breakdowns on a given day?

When a ____________ probability distribution is used to approximate a ____________ probability distribution,we must make a ____________ correction.

The number of standard deviations that a value x is from the mean is a(n)____________.

The cashier service time at the local branch of the Rivertown bank has an exponential distribution with a mean of 2.5 minutes.What is the probability that the service time exceeds 3 minutes?

For a continuous random variable x,the height of the probability curve f(x)at a particular point indicates the value of the probability for that value.

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 and Model Building

Process Improvement Using Control Charts

Filters

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

When a probability distribution is used to approximate a probability distribution,we must make a correction.