Question 1

An aptitude test has a mean score of 80 and a standard deviation of 5.The population of scores is normally distributed.What proportion of tests has scores over 90?

Accepted Answer

A) .9772 
B) .0228 
C) .9544 
D) .0456 
A) .9772 
B) .0228 
C) .9544 
D) .0456

Question 2

If the random variable of x is normally distributed,______ percent of all possible observed values of x will be within three standard deviations of the mean.

Accepted Answer

A) 68.26 
B) 95.44 
C) 99.73 
D) 100 
E) None of these 
A) 68.26 
B) 95.44 
C) 99.73 
D) 100 
E) None of these

Question 3

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

If the distances between the ordered data values are proportional to the distances between the actual values,then the normal probability plot will be a straight line.

Accepted Answer

A) True 
 B)False

Question 5

The weight of a product is normally distributed with a mean of four ounces and a variance of .25 "squared ounces." The company wants to classify the unit as a scrap in a maximum of 1 percent of the units if the weight is below a desired value.Determine the desired weight such that no more than 1 percent of the units are below it.

Accepted Answer

A) 3.360 
B) 3.680 
C) 2.835 
D) 3.418 
A) 3.360 
B) 3.680 
C) 2.835 
D) 3.418

Question 6

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

.0063
Feedback:µ = np = (60)(.

Question 7

Given that the length an athlete throws a hammer is a normal random variable with mean 50 feet and standard deviation 5 feet,what is the probability he throws it no less than 55 feet?

Accepted Answer

A) .8413 
B) .1587 
C) .6826 
D) .3174 
A) .8413 
B) .1587 
C) .6826 
D) .3174

Question 8

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 200?

Accepted Answer

A) 100% 
B) 25% 
C) 0% 
D) 50% 
A) 100% 
B) 25% 
C) 0% 
D) 50%

Question 9

The normal probability distribution is a discrete probability distribution.

Accepted Answer

A) True 
 B)False

Question 10

If the random variable of x is normally distributed,_____ percent of all possible observed values of x will be within two standard deviations of the mean.

Accepted Answer

A) 99.73 
B) 68.26 
C) 95.00 
D) 95.44 
A) 99.73 
B) 68.26 
C) 95.00 
D) 95.44

Question 11

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 12

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 5 ounces?

Accepted Answer

A) .0228 
B) .9772 
C) 0.000 
D) 1.00 
A) .0228 
B) .9772 
C) 0.000 
D) 1.00

Question 13

At an oceanside nuclear power plant,seawater is used as part of the cooling system.This raises the temperature of the water that is discharged back into the ocean.The amount that the water temperature is raised has a uniform distribution over the interval from 10° to 25°C.What is the standard deviation of the temperature increase?

Accepted Answer

A) 10.12 
B) 4.33 
C) 7.50 
D) 
1)25 
A) 10.12 
B) 4.33 
C) 7.50 
D) 
1)25

Question 14

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 $1.10.80 percent of the households spent more than what amount?

Accepted Answer

A) $7.30 
B) $7.38 
C) $9.06 
D) $9.14 
A) $7.30 
B) $7.38 
C) $9.06 
D) $9.14

Question 15

The standard deviation 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 16

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 17

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.Suppose that in an effort to provide better service to the public,the director of the local office is permitted to provide discounts to those individuals whose waiting time exceeds a predetermined time.The director decides that 15 percent of the customers should receive this discount.What are the numbers of minutes they need to wait to receive the discount?

Accepted Answer

A) 34.48 
B) 21.68 
C) 38.32 
D) 25.52 
A) 34.48 
B) 21.68 
C) 38.32 
D) 25.52

Question 18

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 19

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 the 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 20

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

An aptitude test has a mean score of 80 and a standard deviation of 5.The population of scores is normally distributed.What proportion of tests has scores over 90?

If the random variable of x is normally distributed,______ percent of all possible observed values of x will be within three standard deviations of the mean.

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

If the distances between the ordered data values are proportional to the distances between the actual values,then the normal probability plot will be a straight line.

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.

Given that the length an athlete throws a hammer is a normal random variable with mean 50 feet and standard deviation 5 feet,what is the probability he throws it no less than 55 feet?

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 200?

The normal probability distribution is a discrete probability distribution.

If the random variable of x is normally distributed,_____ percent of all possible observed values of x will be within two standard deviations of the mean.

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 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 5 ounces?

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 $1.10.80 percent of the households spent more than what amount?

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

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

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

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

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

Comparing Two Means and Two Proportions

Filters

Exam 6: Continuous Random Variables

An aptitude test has a mean score of 80 and a standard deviation of 5.The population of scores is normally distributed.What proportion of tests has scores over 90?

If the random variable of x is normally distributed,______ percent of all possible observed values of x will be within three standard deviations of the mean.

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

If the distances between the ordered data values are proportional to the distances between the actual values,then the normal probability plot will be a straight line.

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.

Given that the length an athlete throws a hammer is a normal random variable with mean 50 feet and standard deviation 5 feet,what is the probability he throws it no less than 55 feet?

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 200?

The normal probability distribution is a discrete probability distribution.

If the random variable of x is normally distributed,_____ percent of all possible observed values of x will be within two standard deviations of the mean.

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 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 5 ounces?

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 $1.10.80 percent of the households spent more than what amount?

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

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

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

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

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

Comparing Two Means and Two Proportions

Filters