Question

A sample of size 144 drawn from a large population has a sample mean of 47 and a sample standard deviation of 8. What is the? 95% confidence interval for the population? mean? Round to one decimal place as needed.

Answer 1

95% confidence interval for $\mu$ is

$\bar{x}$ - t * S / sqrt(n) < $\mu$ < $\bar{x}$ + t * S / sqrt(n)

47 - 1.977 * 8 / sqrt(144) < $\mu$ < 47 + 1.977 * 8 / sqrt(144)

45.7 < $\mu$ < 48.3

95% CI is (45.7 , 48.3)