Question 1

A(n) __________________________________ is a distribution of means obtained from samples of a specific size taken from a population.

Accepted Answer

sampling d

Question 2

The average gas mileage of a certain model car is 28.0 miles per gallon. If the gas mileages are normally distributed with a standard deviation of 0.45 miles per gallon, find the probability that a car has a gas mileage of between 27.8 and 28.2 miles per gallon.

Accepted Answer

A)  0.343 
B)  0.157 
C)  0.403 
D)  0.172 
A)  0.343 
B)  0.157 
C)  0.403 
D)  0.172

Question 3

The length of country and western songs is normally distributed and has a mean of 200 seconds and a standard deviation of 40 seconds. Find the probability that a random selection of 16 songs will have mean length of 186.30 seconds or less. Assume the distribution of the lengths of the songs is normal.

Accepted Answer

A)  0.91 
B)  0.41 
C)  0.09 
D)  0.59 
A)  0.91 
B)  0.41 
C)  0.09 
D)  0.59

Question 4

For a normal distribution curve with a mean of 15 and a standard deviation of 3, which range of the variable defines an area under the curve corresponding to a probability of approximately 68%?

Accepted Answer

A)  from 13.5 to 16.5 
B)  from 12 to 18 
C)  from 15 to 21 
D)  from 9 to 21 
A)  from 13.5 to 16.5 
B)  from 12 to 18 
C)  from 15 to 21 
D)  from 9 to 21

Question 5

Find the probability P(-1.09 < z < 1.06) using the standard normal distribution.

Accepted Answer

A)  0.8410 
B)  0.2824 
C)  0.7176 
D)  0.6744 
A)  0.8410 
B)  0.2824 
C)  0.7176 
D)  0.6744

Question 6

X is a normally distributed random variable with a mean of 7 and a standard deviation of 2.5. Find the value of X for which 70.54% of the area under the distribution curve lies to the right of it. (Note: the diagram is not necessarily to scale.)

Accepted Answer

A)  6.10 
B)  6.32 
C)  5.65 
D)  8.43 
A)  6.10 
B)  6.32 
C)  5.65 
D)  8.43

Question 7

If a normal distribution has a mean of 20 and a standard deviation of 10, then

Accepted Answer

A)  the median is 20 and the mode is 20. 
B)  the median is 10 and the mode is 30. 
C)  the median is 30 and the mode is 10. 
D)  the median is 20 and the mode is 30. 
A)  the median is 20 and the mode is 20. 
B)  the median is 10 and the mode is 30. 
C)  the median is 30 and the mode is 10. 
D)  the median is 20 and the mode is 30.

Question 8

The probability   is 0.3340.

Accepted Answer

A) True 
 B)False

Question 9

For a normal distribution curve with a mean of 7 and a standard deviation of 5, which of the following ranges of the variable will define an area under the curve corresponding to a probability of approximately 34%?

Accepted Answer

A)  from 4.5 to 9.5 
B)  from 2 to 12 
C)  from 7 to 12 
D)  from -3 to 17 
A)  from 4.5 to 9.5 
B)  from 2 to 12 
C)  from 7 to 12 
D)  from -3 to 17

Question 10

The normal distribution curve can be used as a probability distribution curve for normally distributed variables.

Accepted Answer

A) True 
 B)False

Question 11

The average length of crocodiles in a swamp is 12 feet. If the lengths are normally distributed with a standard deviation of 1.9 feet, find the probability that a crocodile is more than 11.5 feet long.

Accepted Answer

A)  0.90 
B)  0.40 
C)  0.10 
D)  0.60 
A)  0.90 
B)  0.40 
C)  0.10 
D)  0.60

Question 12

If a normally distributed group of test scores have a mean of 70 and a standard deviation of 12, find the percentage of scores that will fall below 50.

Accepted Answer

A)  4.75% 
B)  45.25% 
C)  6.75% 
D)  35.54% 
A)  4.75% 
B)  45.25% 
C)  6.75% 
D)  35.54%

Question 13

Find the probability P(0.21 < z < 1.28) using the standard normal distribution.

Accepted Answer

A)  0.3166 
B)  0.6834 
C)  0.8166 
D)  0.4100 
A)  0.3166 
B)  0.6834 
C)  0.8166 
D)  0.4100

Question 14

The _________________ correction factor is important if a relatively large number of samples are taken without replacement from a small population.

Accepted Answer

The answer of The _________________ correction factor is important if...

Question 15

For a normal distribution with a mean of 8 and a standard deviation of 4, the value 6 has a z value of

Accepted Answer

A)  1.5 
B)  -2.5 
C)  -1.5 
D)  -0.5 
A)  1.5 
B)  -2.5 
C)  -1.5 
D)  -0.5

Question 16

Find the z value that corresponds to the given area.

Accepted Answer

A)  1.33 
B)  -0.51 
C)  0.41 
D)  -0.22 
A)  1.33 
B)  -0.51 
C)  0.41 
D)  -0.22

Question 17

The average hourly wage of workers at a fast food restaurant is $6.50/hr. Assume the wages are normally distributed with a standard deviation of $0.45. If a worker at this fast food restaurant is selected at random, what is the probability that the worker earns more than $6.75?

Accepted Answer

A)  28.8% 
B)  27.6% 
C)  42.1% 
D)  5.2% 
A)  28.8% 
B)  27.6% 
C)  42.1% 
D)  5.2%

Question 18

X is a normally distributed random variable with a mean of 9.0 and a standard deviation of 3.00. Find the value x such that P(X < x) is equal to 0.86. (Note: the diagram is not necessarily to scale.)

Accepted Answer

A)  12.24 
B)  10.47 
C)  13.95 
D)  9.00 
A)  12.24 
B)  10.47 
C)  13.95 
D)  9.00

Question 19

A recent study found that the life expectancy of a people living in Africa is normally distributed with an average of 53 years with a standard deviation of 7.5 years. If a person in Africa is selected at random, what is the probability that the person will die before the age of 65?

Accepted Answer

A)  94.5% 
B)  44.5% 
C)  61.0% 
D)  89.0% 
A)  94.5% 
B)  44.5% 
C)  61.0% 
D)  89.0%

Question 20

In order to be accepted into a certain top university, applicants must score within the top 5% on the SAT exam. Given that the exam has a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university?

Accepted Answer

A)  1400 
B)  1330 
C)  1250 
D)  1100 
A)  1400 
B)  1330 
C)  1250 
D)  1100

A(n) __________________________________ is a distribution of means obtained from samples of a specific size taken from a population.

The average gas mileage of a certain model car is 28.0 miles per gallon. If the gas mileages are normally distributed with a standard deviation of 0.45 miles per gallon, find the probability that a car has a gas mileage of between 27.8 and 28.2 miles per gallon.

For a normal distribution curve with a mean of 15 and a standard deviation of 3, which range of the variable defines an area under the curve corresponding to a probability of approximately 68%?

Find the probability P(-1.09 < z < 1.06) using the standard normal distribution.

X is a normally distributed random variable with a mean of 7 and a standard deviation of 2.5. Find the value of X for which 70.54% of the area under the distribution curve lies to the right of it. (Note: the diagram is not necessarily to scale.)

If a normal distribution has a mean of 20 and a standard deviation of 10, then

The probability is 0.3340.

For a normal distribution curve with a mean of 7 and a standard deviation of 5, which of the following ranges of the variable will define an area under the curve corresponding to a probability of approximately 34%?

The normal distribution curve can be used as a probability distribution curve for normally distributed variables.

The average length of crocodiles in a swamp is 12 feet. If the lengths are normally distributed with a standard deviation of 1.9 feet, find the probability that a crocodile is more than 11.5 feet long.

If a normally distributed group of test scores have a mean of 70 and a standard deviation of 12, find the percentage of scores that will fall below 50.

Find the probability P(0.21 < z < 1.28) using the standard normal distribution.

The _________________ correction factor is important if a relatively large number of samples are taken without replacement from a small population.

For a normal distribution with a mean of 8 and a standard deviation of 4, the value 6 has a z value of

Find the z value that corresponds to the given area.

The average hourly wage of workers at a fast food restaurant is $6.50/hr. Assume the wages are normally distributed with a standard deviation of $0.45. If a worker at this fast food restaurant is selected at random, what is the probability that the worker earns more than $6.75?

X is a normally distributed random variable with a mean of 9.0 and a standard deviation of 3.00. Find the value x such that P(X < x) is equal to 0.86. (Note: the diagram is not necessarily to scale.)

A recent study found that the life expectancy of a people living in Africa is normally distributed with an average of 53 years with a standard deviation of 7.5 years. If a person in Africa is selected at random, what is the probability that the person will die before the age of 65?

In order to be accepted into a certain top university, applicants must score within the top 5% on the SAT exam. Given that the exam has a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university?

The Nature of Probability and Statistics

Frequency Distributions and Graphs

Data Description

Probability and Counting Rules

Discrete Probability Distributions

Confidence Intervals and Sample Size

Hypothesis Testing

Testing the Difference Between Two Means, Two Variances, and Two Proportions

Correlation and Regression

Other Chi-Square Tests

Analysis of Variance

Nonparametric Statistics

Sampling and Simulation

Filters

Exam 6: The Normal Distribution

A(n) __________________________________ is a distribution of means obtained from samples of a specific size taken from a population.

The average gas mileage of a certain model car is 28.0 miles per gallon. If the gas mileages are normally distributed with a standard deviation of 0.45 miles per gallon, find the probability that a car has a gas mileage of between 27.8 and 28.2 miles per gallon.

For a normal distribution curve with a mean of 15 and a standard deviation of 3, which range of the variable defines an area under the curve corresponding to a probability of approximately 68%?

Find the probability P(-1.09 < z < 1.06) using the standard normal distribution.

X is a normally distributed random variable with a mean of 7 and a standard deviation of 2.5. Find the value of X for which 70.54% of the area under the distribution curve lies to the right of it. (Note: the diagram is not necessarily to scale.)

If a normal distribution has a mean of 20 and a standard deviation of 10, then

The probability is 0.3340.

For a normal distribution curve with a mean of 7 and a standard deviation of 5, which of the following ranges of the variable will define an area under the curve corresponding to a probability of approximately 34%?

The normal distribution curve can be used as a probability distribution curve for normally distributed variables.

The average length of crocodiles in a swamp is 12 feet. If the lengths are normally distributed with a standard deviation of 1.9 feet, find the probability that a crocodile is more than 11.5 feet long.

If a normally distributed group of test scores have a mean of 70 and a standard deviation of 12, find the percentage of scores that will fall below 50.

Find the probability P(0.21 < z < 1.28) using the standard normal distribution.

The _________________ correction factor is important if a relatively large number of samples are taken without replacement from a small population.

For a normal distribution with a mean of 8 and a standard deviation of 4, the value 6 has a z value of

Find the z value that corresponds to the given area.

The average hourly wage of workers at a fast food restaurant is $6.50/hr. Assume the wages are normally distributed with a standard deviation of $0.45. If a worker at this fast food restaurant is selected at random, what is the probability that the worker earns more than $6.75?

X is a normally distributed random variable with a mean of 9.0 and a standard deviation of 3.00. Find the value x such that P(X < x) is equal to 0.86. (Note: the diagram is not necessarily to scale.)

A recent study found that the life expectancy of a people living in Africa is normally distributed with an average of 53 years with a standard deviation of 7.5 years. If a person in Africa is selected at random, what is the probability that the person will die before the age of 65?

In order to be accepted into a certain top university, applicants must score within the top 5% on the SAT exam. Given that the exam has a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university?

The Nature of Probability and Statistics

Frequency Distributions and Graphs

Data Description

Probability and Counting Rules

Discrete Probability Distributions

Confidence Intervals and Sample Size

Hypothesis Testing

Testing the Difference Between Two Means, Two Variances, and Two Proportions

Correlation and Regression

Other Chi-Square Tests

Analysis of Variance

Nonparametric Statistics

Sampling and Simulation

Filters