Deck 12: Sampling: Final and Initial Sample Size Determination

Question 1

The z value for a point is the number of standard deviations a point is away from the mean.

Answer 1

False

Question 2

The sampling distribution is the probability of the values of a sampling statistic computed for each possible sample that could be drawn from the target population under a specified sampling plan.

Answer 2

False

Question 3

The confidence interval approach to sample size determination is based on the construction of confidence intervals around the means or proportions using the standardized variate formula.

Answer 3

False

Question 4

Survey System (www.surveysystem.com)and the Discovery Research Group (www.drgutah.com)are Web sites on the Internet that offer free use of sample size and/or confidence interval calculators.

Question 5

In the statistical approach to determining sample size,the precision level is specified in the end.

Question 6

Assuming no measurement error,the reliability of an estimate of a population parameter can be assessed in terms of its standard error.

Question 7

The statistical approach to determining sample size is based on the construction of confidence intervals around sample means or proportions.

Question 8

When using the confidence interval approach to sample size determination,if the statistic of interest is a proportion,rather than a mean,the approach to sample size determination is very different.

Question 9

If the researcher is required to estimate several parameters,not just one,the calculation of sample size in these cases should be based on a consideration of all the parameters that must be estimated.

Question 10

The process of generalizing the sample results to the population results is called statistical inference.

Question 11

The confidence level is the range into which the true population parameter will fall,assuming a given level of confidence.

Question 12

When using the confidence interval approach to sample size determination,in some cases,precision is specified in relative rather than absolute terms.In other words,it may be specified that the estimate be within plus or minus R percentage points of the mean.

Question 13

The concept of a sampling distribution enables us to use probability theory to make inferences about the population values.

Question 14

When the sample size is 10 percent or more of the population size,the standard error formulas will overestimate the standard deviation of the population mean or proportion.Hence,these should be adjusted by a finite population correction factor.

Question 15

The statistically determined sample size is the net or final sample size the sample remaining after eliminating potential respondents who do not qualify or who do not complete the interview.

Question 16

Specify the level of confidence is the first step in the confidence interval approach to determining sample size.

Question 17

When determining the sample size,if the population standard deviation,s,is unknown and an estimate is used,the standard deviation should be re-estimated once the sample has been drawn.Next a revised confidence interval should be calculated to determine the precision level actually obtained.

Question 18

The confidence level is the probability that a confidence interval will include the population parameter.

Question 19

The sampling distribution of the mean is a binomial distribution.

Question 20

Two major nonresponse issues in sampling are improving response rates and adjusting for nonresponse.

Question 21

Suppose a simple random sample of five hospitals is to be drawn from a population of 20 hospitals.There are 15,504 different samples of size 5 that can be drawn.The relative frequency distribution of the values of the mean of these 15,504 different samples would specify the ________ of the mean.

A) confidence level
B) sampling distribution
C) confidence interval
D) normal distribution

Question 22

When conducting marketing research in foreign countries,statistical estimation of sample size may be difficult as estimates of the population mean may be unavailable.

Question 23

The mathematical symbols "π" and "p" represent a ________ for the population and the sampling distribution respectively.

A) proportion
B) standard error of the mean
C) standard deviation
D) variance

Question 24

Prior notification increases response rates for samples of the general public because it reduces surprise and uncertainty and creates a more cooperative atmosphere.

Question 25

A ________ is a summary description of a fixed characteristic or measure of the target population.It denotes the true value that would be obtained if a census rather than a sample was undertaken.

A) precision level
B) finite population correction
C) parameter
D) statistic

Question 26

Trend analysis is an attempt to discern a trend between early and late respondents.

Question 27

Information on differences between respondents and nonrespondents may be obtained from the sample itself,or it may be possible to estimate the differences from other sources.

Question 28

Nonresponse rates should always be reported and,whenever possible,the effects of nonresponse should be estimated.

Question 29

Prepaid incentives have been shown to increase response rates to a greater extent than promised incentives.

Question 30

The ________ is a correction for overestimation of the variance of a population parameter,e.g. ,a mean or proportion,when the sample size is 10 percent or more of the population size.

A) finite population correction
B) parameter
C) precision level
D) statistic

Question 31

If statistical estimation of sample size is at all attempted,it should be realized that the estimates of the population variance don't vary from country to country.

Question 32

A ________ is a summary description of a characteristic or measure of the sample.It is used as an estimate of the population parameter.

A) statistic
B) finite population correction
C) parameter
D) precision level

Question 33

High response rates decrease the probability that nonresponse bias is substantial.

Question 34

When estimating a population parameter by using a sample statistic,the ________ is the desired size of the estimating interval.This is the maximum permissible difference between the sample statistic and the population parameter.

A) finite population correction
B) precision level
C) parameter
D) statistic

Question 35

The mathematical symbols "σX" and "SX" represent a ________ for the population and the sampling distribution respectively.

A) standard deviation
B) standard error of the mean
C) proportion
D) variance

Question 36

Because low response rates increase the probability of response bias,an attempt should always be made to improve the response rate.

Question 37

The ________ is the standard deviation of the sampling distribution of the mean or proportion.

A) variance
B) standard error
C) standard deviation
D) standardized variate

Question 38

The ________ is called the standard error of the mean or the proportion to indicate that it refers to a sampling distribution of the mean or the proportion,and not to a sample or a population.

A) standard deviation
B) standardized variate
C) coefficient of variation
D) variance

Question 39

By inflating the standard deviation,it is possible to increase the sample size and thus the project revenue for the research firm.

Question 40

The door-in-the-face attempt at motivating potential respondents is more effective than foot-in-the-door.

Question 41

Which survey method has the highest refusal rate?

A) mall intercept
B) mail surveys
C) Internet
D) telephone

Question 42

Which method of improving response rate involves use of the foot-in-the-door or door-in-the-face technique?

A) motivating the respondents
B) incentives
C) prior notification
D) follow-up

Question 43

The number of units that will have to be sampled will be determined by the ________.

A) incidence rate
B) completion rate
C) initial sample size
D) final sample size

Question 44

Which equation is the correct equation for determining the initial sample size?

A) $\frac { \text{Final Sample Size \(\times\) Incidence Rate } } { \text{Completion Rate}}$
B) $\frac { \text{Final Sample Size \(\times\) Completion Rate } } { \text{Incidence Rate}}$
C) $\frac { \text{Completion Rate } } { \text{Incidence Rate × Final Sample Size}}$
D) $\frac { \text{Final Sample Size } } { \text{Incidence Rate \(\times\) Completion Rate}}$

Question 45

n = $\frac { \sigma ^ { 2 } z ^ { 2 } } { D ^ { 2 } }$
Based on the above formula for sample size,sample size increases with increases in all of the items below except ________.

A) sample size increases with an increase in the precision level required of the estimate
B) sample size increases with an increase in the population variability
C) sample size increases with an increase in the degree of confidence
D) All of the above are true.Sample size increases with increases in all of the items above.

Question 46

The statistically determined sample size is the net or ________.

A) incidence rate
B) completion rate
C) initial sample size
D) final sample size

Question 47

The rate of occurrence of persons eligible to participate in the study expressed as a percentage is the ________.

A) initial sample size
B) completion rate
C) incidence rate
D) final sample size

Question 48

In ________,cost does not enter directly into the calculation of sample size.

A) simple random sampling
B) cluster sampling
C) stratified sampling
D) A and C are correct

Question 49

Which formula would be used to determine the sample size using the formula for the standard error of the proportion?

A) $$n = \frac { \sigma ^ { 2 } z ^ { 2 } } { D ^ { 2 } }$$
B) $$n = \frac { \pi ( 1 - \pi ) z ^ { 2 } } { D ^ { 2 } }$$
C) $$\sigma _ { X } = D / z$$
D) A and C are correct

Question 50

Which of the formulas below would be used to determine the sample size using the formula for the standard error of the mean?

A) $$n = \frac { \sigma ^ { 2 } z ^ { 2 } } { D ^ { 2 } }$$
B) $$n = \frac { \pi ( 1 - \pi ) z ^ { 2 } } { D ^ { 2 } }$$
C) $$\sigma X = D / z$$
D) A and C are correct.

Question 51

The equation for a 95% confidence interval is: ________.

A) $$\bar { X } \pm 1.960 \mathrm { X }$$
B) $$\bar { X } \pm 1.650 \mathrm { X }$$
C) $$\bar { X } = 1.65 \sigma _ { X } ^ { 2 }$$
D) A,B,C are incorrect

Question 52

Which method of improving response rate involves sending potential respondents a letter notifying them of the imminent mail,telephone,personal,or Internet survey?

A) motivating the respondents
B) incentives
C) follow-up
D) prior notification

Question 53

The ________ for a point is the number of standard errors a point is away from the mean.

A) coefficient of variation
B) variance
C) z-value
D) standard deviation

Question 54

A recent study conducted by CMOR study indicated that consumers prefer ________ surveys versus the ________ method of surveys.

A) telephone;Internet
B) Internet;telephone
C) Internet;mail
D) mail;telephone

Question 55

When determining the sample size,the standard deviation may not be known.Which of the following was not mentioned in your text as a way to estimate the standard deviation?

A) estimate from the mean
B) conduct a pilot study
C) estimate based on researcher judgment
D) consult secondary sources

Question 56

Which statement is not true about nonresponse issues in sampling?

A) Response rates themselves do not indicate whether the respondents are representative of the original sample.
B) Increasing the response rate may not reduce nonresponse bias.
C) For a given study,if the nonrespondents differ from the respondents on the characteristics of interests,the sample estimates will only be mildly biased.
D) Nonresponse error is one of the most significant problems in survey research.

Question 57

The percentage of qualified respondents who complete the interview is the ________.

A) completion rate
B) final sample size
C) initial sample size
D) incidence rate

Question 58

Most refusals occur ________.

A) when the potential respondent first opens the mail package
B) immediately after the interviewer's opening remarks
C) Both A and B are correct.
D) when the potential respondent is well into the interview

Question 59

Which method of improving response rate involves offering potential respondents monetary and non-monetary gifts?

A) follow-up
B) prior notification
C) motivating the respondents
D) incentives

Question 60

The number of interviews that must be completed is the ________.

A) initial sample size
B) completion rate
C) final sample size
D) incidence rate

Question 61

Discuss what can be done to reduce not-at-homes.

Question 62

Which statement is not true about not-at-homes?

A) Consumers are more likely to be at home on weekdays than on weekends.
B) Consumers are more likely to be at home in the evening as opposed to during the afternoon.
C) People with small children are more likely to be at home than single or divorced people.
D) Pre-notification and appointments increase the likelihood that the respondent will be at home when contact is attempted.

Question 63

________ is a method to adjust for nonresponse by assigning the characteristic of interest to the nonrespondents based on the similarity of the variables available for both nonrespondents and respondents.

A) Trend analysis
B) Weighting
C) Subjective estimates
D) Imputation

Question 64

Which method of adjusting for nonresponse involves evaluating the likely effects of nonresponse based on experience and available information?

A) replacement
B) subjective estimates
C) sub-sampling of nonrespondents
D) substitution

Question 65

________ is a method of adjusting for nonresponse in which the researcher tries to discern a trend between early and late respondents.This trend is projected to nonrespondents to estimate their characteristic of interest.

A) Imputation
B) Subjective estimates
C) Subsampling of nonrespondents
D) None of the above are correct.

Question 66

Discuss why there may be ethical concerns when using the standard deviation of a variable in determining sample size.

Question 67

Discuss four of the methods of reducing refusals to participate in a survey.

Question 68

________ is a statistical procedure that attempts to account for nonresponse by assigning differential weights to the data depending on the response rates.

A) Trend analysis
B) Imputation
C) Weighting
D) Subjective estimates

Question 69

Ethical dilemmas associated with sample size determination include all of the following except ________.

A) what should be done when a difference in the actual standard deviation and the estimated standard deviation results in a larger confidence interval than desired
B) inflating the standard deviation to increase sample size and project revenue
C) investigating the possibility of non-response bias and making a reasonable effort to adjust for it
D) All of the above pose ethical dilemmas.

Question 70

Which method of adjusting for nonresponse has the researcher contacting a sub-sample of the nonrespondents;projecting the values obtained from the sub-sample to all respondents;then adjusting the survey results to account for nonresponse?

A) substitution
B) replacement
C) sub-sampling of nonrespondents
D) subjective estimates

Question 71

Which method of improving response rate involves sending potential respondents a postcard or letter to remind nonrespondents to complete and return the questionnaire?

A) motivating the respondents
B) incentives
C) prior notification
D) follow-up