Statistics Problem: Effective Manufacturing Adjustments

The datain the attachment provides two random samples from two successive days runs of a product. You adjusted the manufacturing process after the first day in an attempt to decrease the meanvalue. Using interval estimates, to a 95% confidence level, was your most recent adjustment effective?

First, we figure out the mean and standard deviation for group 1 and group 2 respectively.
u1=average(A1:A50)=100.0878, s1=stdev(A1:A50)=5.0562
u2=average(B1:B50)=98.0644, …

The expert examines effective manufacturing adjustments.