Question

A statistics professor drew a random sample of 81 observations and found that x with bar on top equals 62 s equals 15. Estimate the LCL of the population mean with 90% confidence. Report your answer to two decimal places.

Answer 1

LCL = 59.26 to two decimal places

Explanation:

Here, we want to estimate the LCL of the population mean with 90% confidence

We proceed as follows;

Given alpha = 0.1, then Z(0.05)=1.645 (from standard normal table), s = 15

Mathematically;

LCL =x_bar -Z*s/√( n)= 62 - (1.645 * 15)/√81

LCL = 62- (24.675)/9 = 59.2583

LCL = 59.26 to two decimal places