Which of the Following Statements Is NOT a Valid Rule

Multiple Choice

Which of the following statements is NOT a valid rule for determining sample size?

A) Sample sizes larger than 30 and less than 500 are appropriate for most research.
B) Sample sizes smaller than 30 and larger than 500 are inappropriate for most research.
C) Sample size should be about 10 times larger than the number of variables measured in a study.
D) With tight controls, experimental research can be successful with samples as small as 10.