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 null hypothesis to be tested is H₀: μd = 0.The test statistic is

A) -1.96.
B) 1.77.
C) 0.
D) 1.00.