You are going to use a purposive sample (a nonprobability sample) to collect data from fast-food restaurant customers. Which of the following concepts would be applicable to determining sample size?
A) Confidence intervals
B) Sample size formula for estimating a percentage
C) Sample size formula for estimating a mean
D) Estimating a population value within a stated percent of allowable error
E) None of the above would be appropriate; sample size concepts and formulas are only applicable when probability sampling plans have been used.
Answer: D) Estimating a population value within a stated percent of allowable error