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

Multiple Choice

Find the standardized test statistic to test the hypothesis that $\mu _ { 1 } = \mu _ { 2 }$ . Two samples are randomly selected from each population. The sample statistics are given below. Use $\alpha = 0.05$ .
$$\begin{array} { l l } \mathrm { n } _ { 1 } = 50 & \mathrm { n } _ { 2 } = 60 \\\overline { \mathrm { x } } 1 = 21 & \overline { \mathrm { x } _ { 2 } } = 19 \\\mathrm {~s} 1 = 1.5 & \mathrm {~s} _ { 2 } = 1.9\end{array}$$

A) 6.2
B) 8.1
C) 4.2
D) 3.8