Question

In a sample of 100 steel canisters, the mean wall thickness was 8.1 mm with a standard deviation of 0.5 mm.

Find a 95% lower confidence bound for the mean wall thickness. (Round the final answer to three decimal places.)

The 95% lower confidence bound is

Answer 1

Solution :

Given that,

t ,df = 1.660

Margin of error = E = t,df * (s /n)

= 1.660 * (0.5 / 100)

Margin of error = E = 0.083

The 95% lower confidence interval estimate of the population mean is,

- E

8.1 - 0.083

8.017

The 95% lower confidence bound is 8.017