To estimate a population mean, the sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is _____.
A) 10
B) 11
C) 116
D) 117

Question

Quizplus · Accepted Answer

To find the sample size (n), use the formula for margin of error: ME = Z * (σ/√n). For a 95% confidence level, Z is approximately 1.96. Set ME to 2 and solve for n: 2 = 1.96 * (11/√n). Solving gives n ≈ 116.48, which rounds up to 117.

To Estimate a Population Mean, the Sample Size Needed to Provide