A product is produced by two different machines. Two random samples were selected, and the following summary information were computed accordingly:
Machine 1 Machine 2
Sample Size 80 100
Sample Mean 4.5gm 4.4gm
Population Standard Deviation 0.5gm 0.6gm
a) Estimate the confidence interval of the difference between the two means with 80% confidence level. (show all work).
b) What are the assumptions you considered for the above solution?