Past experience has indicated that the breaking strength of yarn used in manufacturing drapery material is normally distributed and that σ = 4 psi. a random sample of 8 specimens is tested, and the average breaking strength is found to be 98 psi. find a 95% two-sided confidence interval on the true mean breaking strength. round the answers to 1 decimal place.

Step-by-step explanation:

Given : Past experience has indicated that the breaking strength of yarn used in manufacturing drapery material is normally distributed and that σ = 4 psi.

A random sample of 8 specimens is tested, and the average breaking strength is found to be 98 psi.

i.e. n= 8  and

Critical value for 95% confidence =

Confidence interval for population mean :-

i.e.

Hence,  a 95% two-sided confidence interval on the true mean breaking strength. =

-2 is the right