The Following Samples Are Observations Taken from the Same Elements

Multiple Choice

The following samples are observations taken from the same elements at two different times: Assume that the populations are normally distributed and construct a 90% confidence interval for the difference in the means of the distribution at the times in which the samples were taken.

A) (7.6232, 13.4434)
B) (5.2825, 15.8127)
C) (6.8212, 14.7821)
D) (7.4122, 14.6801)