posted by jp on .
In order to test a new production method, 36 employees were selected randomly to try the new method. The mean was 75.79 parts per hour with a standard deviation of 28.25 parts per hour.
Calculate a 95% confidence interval for the true mean production rate for the new method.
95% = mean ± 1.96 SEm
SEm = SD/√n
You can do the calculations.