mktg 470 - chapter 9b - sample size

why does sample size matter?

it can save you a lot of costs if you calculate the correct sample size(overdoing it is a waste)

what is a sample size decision normally a compromise of?

what is theoretically perfect and what is practically feasible

does sample size affect representativeness?

no

what is sample size accuracy?

closeness of findings to the true population value

what is sample size is related to what?

accuracy

what determines whether a sample will be representative or not?

the sampling method. probability sample is truly representative

the size of your sample will boost the…?

accuracy

what are some crucial concepts of creating optimal sample sizes?

sample size, accuracy, variability, confidence interval

what is the only perfectly accurate sample?

a census → measures every member of the population

what is sampling error?

consequence of sampling, and is influenced by sample size

what is a nonsampling error?

all other errors (question bias, wrong problem definition, mistakes in analyses, etc.)

why will some probability samples always have some inaccuracy?

no random sample’s value is a perfectly accurate reflection of the populations value

the larger a probability sample, the more…

accurate

what is the law of diminishing returns?

once a sample is larger than 1000, large gains in accuracy are not realized even with large increases in sample size

what is the sample error formula?

sample error = 1.96*sqrt (p*q/n)

what is variability?

the amount of disagreement (dissimilarity vs. similarity; variance) in respondents’ answers to a specific question

what does a high consensus within a group mean for variability?

low variability

what does a low consensus within a group mean for variability?

high variability

what combination is the largest possible variability?

p = 50, q = 50

what is a confidence interval?

range whose endpoints define a certain % of the responses to a question

what allows us to assume a normal (bell-shaped) curve of the results of repeated surveys?

the central limit theorem

in almost all cases, the sample error of a probability sample is __ of the size of the population

probability sample

the size of a probability sample depends on trade-off between…

desired accuracy and cost of data collection

what are the components to creating a proper sample size?

variability, acceptable sample error, and the level of confidence interval

how do we determine the amount of acceptable sample error?

based on the accuracy of the results.

how to balance sample size with cost of data collection?

Researchers should work with managers to take cost into consideration in this decision

what are some methods of sample size determination?

arbitrary, conventional specification, cost basis

what is conventional sample size specification?

following conventions or beliefs, adopting past sample sizes

what is the cost basis of sample size specification?

“all you can afford” budget