When Conducting Hypothesis Tests for Two Sample Means,the Term M₁

Multiple Choice

When conducting hypothesis tests for two sample means,the term m₁ - m₂ in 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.