Question

We have productivity data from 2 mills

Data from Mill 1: 1, 10, 18, 21, 22, 22, 23, 25, 28, 29, 32, 34, 38, 40, n=13, Σx=342, Σx^2= 9836

Data from Mill 2: 13, 13, 13, 15, 18, 18, 18, 19, 19, 19, 21, 22, 22, 23, 23, 24, 27, 31, n=18, Σx=358, Σx^2= 7520

a) Calculate the mean and standard deviation for Mill 1

b) Calculate the mean and standard deviation for Mill 2

c) Assume the two are normal distributions, and the standard deviations are correct for the two populations the mills are drawn from. Finally assume the mean for the two distributions are the same.

i) Use the variance rules to calculate the variance of the difference of the means.

ii)Calculate the Z score for the difference of the means

  iii)Determine the probability of seeing that Z Score or one with a larger absolute value.

Answer 1