Question

A quality control engineer is interested in the mean length of sheet insulation being cut automatically by machine. The desired length of the insulation is 12 ft. It is known that the standard deviation in the cutting length is 0.15 ft. A sample of 70 ut sheets yields a mean length of 12.14 ft. Find the 99% confidence interval for the mean length cut by machine

Answer 1

Formula:

CI99 = mean + or - 2.575(sd/√n)
...where + or - 2.575 represents the 99% confidence interval using a z-table, sd = standard deviation, and n = sample size.

I hope this will get you started.

Answer 2

Thanks:)

Answer 3

789

Answer 4

Thanks