Question 1

Which of the following statements are correct?

Accepted Answer

A) A point estimate is an estimate of the range of a population parameter 
B) A point estimate is a single value estimate of the value of a population parameter 
C) A point estimate is an unbiased estimator if its standard deviation is the same as the actual value of the population standard deviation 
D) All of these options

Question 2

A probability sample is a sample in which the sampling units are chosen from the population by means of a random mechanism such as a random number table.

Accepted Answer

A) True 
 B)False

Question 3

The theorem that states that the sampling distribution of the sample mean  is approximately normal when the sample size n is reasonably large is known as the:

Accepted Answer

A) central limit theorem 
B) central tendency theorem 
C) simple random sample theorem 
D) point estimate theorem

Question 4

There is approximately _____ % chance that any particular  will be within two standard deviations of the population mean (  ).

Accepted Answer

A) 90 
B) 95 
C) 99 
D) 99.7

Question 5

If a simple random sample of size n is chosen from a population of size N,then each member of the population has probability N / n of being chosen in the sample.

Accepted Answer

A) True 
 B)False

Question 6

A sales manager for a company that makes commercial ovens for restaurants is interested in estimating the average number of restaurants in all metropolitan areas across the entire country.He does not have access to the data for each metropolitan location,so he had decided to select a sample that will be representative of all such areas,and will use a sample size of 30.Do you believe that simple random sampling is the best approach to obtaining a representative subset of the metropolitan areas in the given frame? Explain.If not,recommend how the sales manager might proceed to select a better sample of size 30 from this data?

Accepted Answer

The answer of A sales manager for a company that...

Question 7

Measurement error occurs when:

Accepted Answer

A) a portion of the sample does not respond to the survey 
B) the sample responses are not clear 
C) the responses to question do not reflect what the investigator had in mind 
D) the investigator does not correctly tally all responses

Question 8

Which of the following statements correctly describe estimation?

Accepted Answer

A) It is the process of inferring the values of known population parameters from those of unknown sample statistics. 
B) It is the process of inferring the values of unknown sample statistics from those of known population parameters. 
C) It is the process of inferring the values of known sample statistics from those of unknown population parameters. 
D) It is the process of inferring the values of unknown population parameters from those of known sample statistics.

Question 9

The Central Limit Theorem (CLT)says that as long as the sample size is reasonably large,there is about a 95% chance that the magnitude of the sampling error for the mean will be no more than two standard errors.

Accepted Answer

A) True 
 B)False

Question 10

(A)Compute the point estimate of the population mean from the sample above.What is the sampling error in this case? Assume that the population consists of the given 200 customer service times.
(B)Compute the point estimate of the population standard deviation from the sample above.
(C)Should you use the finite population correction (fpc)factor to estimate the standard error of  ? Explain.If your answer is yes,what is the value of the fpc?
(D)Determine a good approximation to the standard error of the mean in this case.

Accepted Answer

The answer of (A)Compute the point estimate of the population...

Question 11

Selecting a random sample from each identifiable subgroup within a population is called:

Accepted Answer

A) random sampling 
B) systematic sampling 
C) stratified sampling 
D) cluster sampling 
E) None of these options

Question 12

When a portion of the sample does not respond to the survey,_____ results.

Accepted Answer

A) measurement error 
B) nonresponse bias 
C) sampling error 
D) systematic failure 
E) nonlinear error

Question 13

The averaging effect means that as you average more and more observations from a given distribution,the variance of the average

Accepted Answer

A) increases 
B) decreases 
C) is unaffected 
D) could either increase,decrease or stay the same

Question 14

(A)What sample size would be required for the production personnel to be approximately 95% sure that their estimate of the average number of errors per issue is within 4 errors of the true mean? Assume that the editor's best estimate of the population standard deviation (  )is 10 errors per issue.
(B)How does your answer to (A)change if the editor wants the estimate to be within 3 errors of the actual population mean? Explain the difference in your answers to (A)and (B).

Accepted Answer

The answer of (A)What sample size would be required for...

Question 15

Simple random sampling can result in under-representation or over-representation of certain segments of the population.This is one of several reasons that simple random samples are almost never used in real applications.

Accepted Answer

A) True 
 B)False

Question 16

A sampling error is the result of:

Accepted Answer

A) measurement error 
B) nonresponse bias 
C) nontruthful responses 
D) bad luck

Question 17

Sampling error is evident when:

Accepted Answer

A) a question is poorly worded 
B) the sample is too small 
C) the sample is not random 
D) the sample mean differs from the population mean

Question 18

A point estimate is a single numeric value,a "best guess" of a population parameter,calculated from the sample data.

Accepted Answer

A) True 
 B)False

Question 19

The Central Limit Theorem (CLT)is generally valid for:

Accepted Answer

A) n > 5 
B) n > 10 
C) n > 20 
D) n > 30 
E) any size n

Question 20

(A)Find the mean and standard deviation of the sampling distribution of the average weekly earnings in the sample.
(B)Find probability that the mean of the sample is less than $445.
(C)Find the probability that the mean of the sample is between $445 and $455.
(D)Find the probability that the mean of the sample is greater than $460.
(E)Explain why the assumption of normality about the distribution of the average weekly earnings for employees was not involved in the answers to (A)through (D).

Accepted Answer

The answer of (A)Find the mean and standard deviation of...

Exam 7: Sampling and Sampling Distributions

Which of the following statements are correct?

A probability sample is a sample in which the sampling units are chosen from the population by means of a random mechanism such as a random number table.

The theorem that states that the sampling distribution of the sample mean is approximately normal when the sample size n is reasonably large is known as the:

There is approximately _____ % chance that any particular will be within two standard deviations of the population mean ( ) .

If a simple random sample of size n is chosen from a population of size N,then each member of the population has probability N / n of being chosen in the sample.

Measurement error occurs when:

Which of the following statements correctly describe estimation?

The Central Limit Theorem (CLT)says that as long as the sample size is reasonably large,there is about a 95% chance that the magnitude of the sampling error for the mean will be no more than two standard errors.

Selecting a random sample from each identifiable subgroup within a population is called:

When a portion of the sample does not respond to the survey,_____ results.

The averaging effect means that as you average more and more observations from a given distribution,the variance of the average

Simple random sampling can result in under-representation or over-representation of certain segments of the population.This is one of several reasons that simple random samples are almost never used in real applications.

A sampling error is the result of:

Sampling error is evident when:

A point estimate is a single numeric value,a "best guess" of a population parameter,calculated from the sample data.

The Central Limit Theorem (CLT) is generally valid for: