A simple random sample of 60 is drawn from a normally distributed population, and the mean is found to be 28, with a standard deviation of 5. Which of the following values is within the 95% confidence interval (z-score = 1.96) for the population mean?

Given:

n = 60, the sample size

μ = 28, the mean

σ = 5, the standard dviation

A 95% confidence level, the confidence (interval is

(μ - 1.96σ/√n, μ + 1.96σ/√n)

= (28 - (1.96*5) / √60, 28 + (1.96*5) / √60)

= (26.735, 29.265)

Answer:

The confidence interval is (26.735, 29.265)

or between 26.735 and 29.265.