Question 1

Errors of nonobservation occur when data values are recorded incorrectly.

Accepted Answer

A) True 
 B)False  False

Question 2

A random sample of size 1,000 is taken from a population where p = .20.Describe the sampling distribution of $\hat { p }$.

Accepted Answer

A)  Cannot be determined
B)  Approximately normal
C)  Skewed to the left
D)  Skewed to the right  B

Question 3

If the sampled population has a mean of 48 and standard deviation of 16,then the mean and the standard deviation for the sampling distribution of $\bar { X }$
For n = 16 are:

Accepted Answer

A)  4 and 1.
B)  12 and 4.
C)  48 and 4.
D)  48 and 1.
E)  48 and 16.  C

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 randomly selected sample of 4 sheets will have an average length of less than 29.9 inches long?

Accepted Answer

A)  .0668
B)  .9332
C)  .0014
D)  .4404

Question 5

If the sampled population is finite and at least _____ times larger than the sample size,we treat the population as infinite.

Accepted Answer

A)  5
B)  20
C)  30
D)  10

Question 6

The diameter of small Nerf balls manufactured at a factory in China is expected to be approximately normally distributed with a mean of 5.2 inches and a standard deviation of .08 inches.Suppose a random sample of 20 balls is selected.What percentage of sample means will be less than 5.14 inches?

Accepted Answer

A)  0.043%
B)  22.66%
C)  4.3%
D)  .00043%

Question 7

Find \(\mathrm { P } ( \bar { X } x = 200,and n = 100.

Accepted Answer

A)  .8413
B)  .4602
C)  .5398
D)  .1587

Question 8

In the upcoming governor's election,the most recent poll,based on 900 respondents,predicts that the incumbent will be reelected with 55 percent of the votes.For the sake of argument,assume that 51 percent of the actual voters in the state support the incumbent governor (p = 0.51).Calculate the probability of observing a sample proportion of voters 0.55 or higher supporting the incumbent governor.

Accepted Answer

A)  .0166
B)  .0247
C)  .0082
D)  .9918

Question 9

The College Student Journal (December 1992)investigated differences in traditional and nontraditional students,where nontraditional students are defined as 25 years old or older and working.Based on the study results,we can assume the population mean and standard deviation for the GPA of nontraditional students is µ = 3.5 and ? = 0.5.Suppose a random sample of 100 nontraditional students is selected and each student's GPA is calculated.Calculate $\sigma _ { \bar { x } }$

Accepted Answer

A)  0.5
B)  3.5
C)  7.0
D)  0.05

Question 10

The diameter of small Nerf balls manufactured at a factory in China is expected to be approximately normally distributed with a mean of 5.2 inches and a standard deviation of .08 inches.Suppose a random sample of 20 balls is selected.Calculate the mean of the sampling distribution of the sample mean.

Accepted Answer

A)  5.2
B)  0.8
C)  0.08
D)  0.018

Question 11

In systematic sampling,the first element is randomly selected from the first (N/n)elements.

Accepted Answer

A) True 
 B)False

Question 12

The chief chemist for a major oil and gasoline production company claims that the regular unleaded gasoline produced by the company contains on average 4 ounces of a certain ingredient.The chemist further states that the distribution of this ingredient per gallon of regular unleaded gasoline is normal and has a standard deviation of 1.2 ounces.What is the probability of finding an average in excess of 4.3 ounces of this ingredient from 100 randomly inspected 1-gallon samples of regular unleaded gasoline?

Accepted Answer

A)  .5987
B)  .4013
C)  .9938
D)  .0062

Question 13

The sampling distribution of $\bar { X }$ 
must be a normal distribution with mean = 0 and standard deviation = 1.

Accepted Answer

A) True 
 B)False

Question 14

If the sampled population distribution is skewed,then in most cases the sampling distribution of the mean can be approximated by the normal distribution if the sample size n is at least 30.

Accepted Answer

A) True 
 B)False

Question 15

A sample size of 500 is sufficiently large to conclude that the sampling distribution of $\hat { p }$ 
is a normal distribution,when the estimate of the population proportion is .995.

Accepted Answer

A) True 
 B)False

Question 16

The mean of the sampling distribution of $\bar { X }$ 
is always equal to the mean of the sampled population.

Accepted Answer

A) True 
 B)False

Question 17

Find $\mathrm { P } ( \bar { X } > 172 )$ If ? = 175 and $\sigma _ { \bar { X } } ^ { 2 } = 9$

Accepted Answer

A)  .1587
B)  .8413
C)  .6293
D)  .3707

Question 18

The chief chemist for a major oil and gasoline production company claims that the regular unleaded gasoline produced by the company contains on average 4 ounces of a certain ingredient.The chemist further states that the distribution of this ingredient per gallon of regular unleaded gasoline is normal and has a standard deviation of 1.2 ounces.What is the probability of finding an average less than 3.85 ounces of this ingredient from 64 randomly inspected 1-gallon samples of regular unleaded gasoline?

Accepted Answer

A)  .1587
B)  .8413
C)  .1357
D)  .8643

Question 19

The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.3 inches.What is the probability that the average length of a steel sheet from a sample of 9 units is more than 29.95 inches long?

Accepted Answer

A)  .4602
B)  .8413
C)  .1587
D)  .5397

Question 20

It has been reported that the average time to download the home page from a government website was 0.9 seconds.Suppose that the download times were normally distributed with a standard deviation of 0.3 seconds.If random samples of 36 download times are selected,calculate the mean of the sampling distribution of the sampling mean.

Accepted Answer

A)  0.3
B)  0.15
C)  0.9
D)  0.05

Exam 7: Sampling and Sampling Distributions

Errors of nonobservation occur when data values are recorded incorrectly.

A random sample of size 1,000 is taken from a population where p = .20.Describe the sampling distribution of $\hat { p }$ .

If the sampled population has a mean of 48 and standard deviation of 16,then the mean and the standard deviation for the sampling distribution of $\bar { X }$ For n = 16 are:

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 randomly selected sample of 4 sheets will have an average length of less than 29.9 inches long?

If the sampled population is finite and at least _____ times larger than the sample size,we treat the population as infinite.

The diameter of small Nerf balls manufactured at a factory in China is expected to be approximately normally distributed with a mean of 5.2 inches and a standard deviation of .08 inches.Suppose a random sample of 20 balls is selected.What percentage of sample means will be less than 5.14 inches?

Find $\mathrm { P } ( \bar { X } < 402 )$ If ? = 400,?_x = 200,and n = 100.

In systematic sampling,the first element is randomly selected from the first (N/n)elements.

The sampling distribution of $\bar { X }$ must be a normal distribution with mean = 0 and standard deviation = 1.

If the sampled population distribution is skewed,then in most cases the sampling distribution of the mean can be approximated by the normal distribution if the sample size n is at least 30.

A sample size of 500 is sufficiently large to conclude that the sampling distribution of $\hat { p }$ is a normal distribution,when the estimate of the population proportion is .995.

The mean of the sampling distribution of $\bar { X }$ is always equal to the mean of the sampled population.

Find $\mathrm { P } ( \bar { X } > 172 )$ If ? = 175 and $\sigma _ { \bar { X } } ^ { 2 } = 9$

The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.3 inches.What is the probability that the average length of a steel sheet from a sample of 9 units is more than 29.95 inches long?

Exam 7: Sampling and Sampling Distributions

Errors of nonobservation occur when data values are recorded incorrectly.

A random sample of size 1,000 is taken from a population where p = .20.Describe the sampling distribution of p^\hat { p }p^​ .

If the sampled population has a mean of 48 and standard deviation of 16,then the mean and the standard deviation for the sampling distribution of Xˉ\bar { X }Xˉ For n = 16 are:

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 randomly selected sample of 4 sheets will have an average length of less than 29.9 inches long?

If the sampled population is finite and at least _____ times larger than the sample size,we treat the population as infinite.

The diameter of small Nerf balls manufactured at a factory in China is expected to be approximately normally distributed with a mean of 5.2 inches and a standard deviation of .08 inches.Suppose a random sample of 20 balls is selected.What percentage of sample means will be less than 5.14 inches?

Find P(Xˉ<402) \mathrm { P } ( \bar { X } < 402 ) P(Xˉ<402) If ? = 400,?x = 200,and n = 100.

In systematic sampling,the first element is randomly selected from the first (N/n)elements.

The sampling distribution of Xˉ\bar { X }Xˉ must be a normal distribution with mean = 0 and standard deviation = 1.

If the sampled population distribution is skewed,then in most cases the sampling distribution of the mean can be approximated by the normal distribution if the sample size n is at least 30.

A sample size of 500 is sufficiently large to conclude that the sampling distribution of p^\hat { p }p^​ is a normal distribution,when the estimate of the population proportion is .995.

The mean of the sampling distribution of Xˉ\bar { X }Xˉ is always equal to the mean of the sampled population.

Find P(Xˉ>172) \mathrm { P } ( \bar { X } > 172 ) P(Xˉ>172) If ? = 175 and σXˉ2=9\sigma _ { \bar { X } } ^ { 2 } = 9σXˉ2​=9

The population of lengths of aluminum-coated steel sheets is normally distributed with a mean of 30.05 inches and a standard deviation of 0.3 inches.What is the probability that the average length of a steel sheet from a sample of 9 units is more than 29.95 inches long?

A random sample of size 1,000 is taken from a population where p = .20.Describe the sampling distribution of $\hat { p }$ .

If the sampled population has a mean of 48 and standard deviation of 16,then the mean and the standard deviation for the sampling distribution of $\bar { X }$ For n = 16 are:

Find $\mathrm { P } ( \bar { X } < 402 )$ If ? = 400,?_x = 200,and n = 100.

The sampling distribution of $\bar { X }$ must be a normal distribution with mean = 0 and standard deviation = 1.

A sample size of 500 is sufficiently large to conclude that the sampling distribution of $\hat { p }$ is a normal distribution,when the estimate of the population proportion is .995.

The mean of the sampling distribution of $\bar { X }$ is always equal to the mean of the sampled population.

Find $\mathrm { P } ( \bar { X } > 172 )$ If ? = 175 and $\sigma _ { \bar { X } } ^ { 2 } = 9$