Find the Standardized Test Statistic to Test the Claim That $\mu _ { 1 } = \mu _ { 2 }$

Multiple Choice

Find the standardized test statistic to test the claim that $\mu _ { 1 } = \mu _ { 2 }$ . Assume the two samples are random and independent.
Population statistics: $\sigma _ { 1 } = 2.5 \text { and } \sigma _ { 2 } = 2.8$ Sample statistics: $\overline { \mathrm { x } } 1 = 3 , \mathrm { n } _ { 1 } = 40 \text { and } \overline { \mathrm { x } } 2 = 4 , \mathrm { n } _ { 2 } = 35$

A) -1.6
B) -0.8
C) -2.6
D) -1.0