A Hypothesis Test Is to Be Performed to Test the Equality

Multiple Choice

A hypothesis test is to be performed to test the equality of two population means. The sample sizes are large and the samples are independent. Give an expression for the population standard deviation of the $\left( \bar { x } _ { 1 } - \bar { x } _ { 2 } \right)$ values in terms of $\mathrm { s } _ { 1 } , \mathrm {~s} _ { 2 } , \mathrm { n } _ { 1 }$ , and $\mathrm { n } _ { 2 }$ .

A) $\sqrt { \frac { \mathrm { s } _ { 1 } ^ { 2 } } { \mathrm { n } _ { 1 } } + \frac { \mathrm { s } _ { 2 } ^ { 2 } } { \mathrm { n } _ { 2 } } }$

B) $\sqrt { \frac { \mathrm { s } _ { 1 } ^ { 2 } } { \mathrm { n } \frac { 2 } { 1 } } + \frac { \mathrm { s } 2 } { \mathrm { n } \frac { 2 } { 2 } } }$

C) $\sqrt { \frac { \mathrm { s } _ { 1 } ^ { 2 } } { \mathrm { n } _ { 1 } } - \frac { \mathrm { s } _ { 2 } ^ { 2 } } { \mathrm { n } _ { 2 } } }$

D) $\frac { \mathrm { s } _ { 1 } ^ { 2 } } { \mathrm { n } _ { 1 } } + \frac { \mathrm { s } _ { 2 } ^ { 2 } } { \mathrm { n } _ { 2 } }$