It is known that the population variance equals 484. With a 0.95 probability, the sample size that needs to be taken to estimate the population mean if the desired margin of error is 5 or less is
A)25
B)74
C)189
D)75

Question

Quizplus · Accepted Answer

To find the sample size, use the formula for the margin of error in estimating a population mean: E = Z * (σ/√n), where E is the margin of error, Z is the Z-score for the desired confidence level (1.96 for 95%), σ is the population standard deviation (√484 = 22), and n is the sample size. Solving for n when E = 5 gives n ≈ 74.5, which rounds up to 75.

It Is Known That the Population Variance Equals 484