When Conducting Hypothesis Tests for Two Sample Means, the Term

Multiple Choice

When conducting hypothesis tests for two sample means, the term μ 1- μ 2in the numerator of the formula reduces to zero because________.

A) the standard deviations are calculated first.
B) the tests are conducted at very low alpha levels.
C) the samples are independent as well as random.
D) the null hypothesis is assumed to be true.