Question

Determine the minimum sample size required when you want to be 98% confident that the sample mean is within two units of the population mean. Assume a population standard deviation of 7.55 in a normally distributed population.

Answer 1

Answer: n = 78

Therefore, Determine the minimum sample size required when you want to be 98% confident that the sample mean is within two units of the population mean is 78

n >/= 78

Explanation:

Given;

Standard deviation r= 7.55

Margin of error E= 2.0

Confidence interval of 98%

Z at 98% = 2.33

Margin of error E = Z(r/√n)

Making n the subject of formula, we have

n = (Z×r/E)^2

n = (2.33 × 7.55/2.0)^2

n = (8.79575)^2

n = 77.3652180625

n >/= 78

Therefore, Determine the minimum sample size required when you want to be 98% confident that the sample mean is within two units of the population mean is 78