When Testing for the Significance of the Difference Between Two $\bar { X } _ { 1 } = \bar { X } _ { 2 }$

Multiple Choice

When testing for the significance of the difference between two sample means,the null hypothesis can be stated as

A) $\bar { X } _ { 1 } = \bar { X } _ { 2 }$
B) m > 0.
C) m = m.
D) s = s.