Given that the population standard deviation is 3.7, what sample size is required to be 95% confident that the estimated mean has an error less than 0.05?
OPTIONS
- 783
- 42074
- 21037
- 412
ANSWER
21037
EXPLANATION
If the sample average is used to estimate the population mean, the confidence that the error will not exceed E is (1-alpha). The same size is computed by the expression: n = Z2sigma2 / E2 n = (1.96)2 * (3.7)2/(0.05)2 n = 21037
