Test the Hypothesis That $\mu _ { 1 } \neq \mu _ { 2 }$

Essay

Test the hypothesis that $\mu _ { 1 } \neq \mu _ { 2 }$ . Two samples are randomly selected from normal populations. The sample statistics are given below.
$$\begin{array} { l l } \mathrm { n } _ { 1 } = 11 & \mathrm { n } _ { 2 } = 18 \\\overline { \mathrm { x } } 1 = 7.8 & \overline { \mathrm { x } } 2 = 8.2 \\\mathrm {~s} _ { 1 } = 0.76 & \mathrm {~s} _ { 2 } = 0.51\end{array}$$