Question

The average weight loss of n = 16 grinding spheres after a certain period in milling work is 3.42 g. with a standard deviation of 0.68 g. Find an 80% confidence interval for the actual mean weight loss of these crushing spheres under the stated conditions.

Answer 1

Solution :

Given that,

t /2,df = 1.341

Margin of error = E = t/2,df * (s /n)

= 1.341 * (0.68 / 16)

Margin of error = E = 0.23

The 80% confidence interval estimate of the population mean is,

- E < < + E

3.42 - 0.23 < < 3.42 + 0.23

3.19 < < 3.65

(3.19 , 3.65)