Mkt 232 Chapter 13

Front 1

number of units to be sampled

Back 1

sample size

Front 2

refers to how close a random sample's statistic is to the true population's value it represents

Back 2

sample accuracy

Front 3

- the only perfectly accurate sample is a census
- a probability sample will always have some inaccuracy (sample error)
- the larger the probability is, the more accurate it is (less sample error)
- probability sample accuracy (error) can be calculated with a simple formula, and expressed as a +/- % number
- you can take any finding in the survey, replicate the survey with the same probability sample size, and you will be "very likely" to find the same finding within the +/- % range of the original finding
- in almost all cases, the accuracy (sample error) of a probability sample is independent of the size of the population
- a probability sample size can be a very tiny percent of the population size and still be very accurate (have little sample error)
- the size of a probability sample depends on the client's desired accuracy (acceptable sample error) balance against the cost of data collection for that sample size

Back 3

axioms of sample size and sample accuracy

Front 4

the larger a probability sample is, the more accurate it is (less sample error)

Back 4

relationship of sample size to accuracy

Front 5

correct method by which to determine sample size
- accuracy
- variability
- confidence interval
- "correct"sample size

Back 5

confidence interval method of determining sample size

Front 6

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

Back 6

confidence interval

Front 7

refers to how similar or dissimilar responses are to a given question

Back 7

variability

Front 8

the amount of sample error that will be associated with the survey

Back 8

acceptable error

Front 9

percent of area under the normal curve described by our calculated confidence intervals

Back 9

level of confidence

Front 10

n = z2(pq)/e2

Back 10

sample size formula

Front 11

worst case: variability is 50%/50%

Back 11

estimating variability: highest amount of variability