The Following Information Was Obtained from Matched Samples Taken from Two

Multiple Choice

The following information was obtained from matched samples taken from two populations. The daily production rates for a sample of workers before and after a training program are shown below. Assume the population of differences is normally distributed. ​
The point estimate for the difference between the means of the two populations is

A) -1.
B) -2.
C) 0.
D) 1.