Test Hypotheses Regarding the Difference of Two Independent Means
-A $\alpha = 0.05$

Test Hypotheses Regarding the Difference of Two Independent Means
-A university wanted to see whether there was a significant difference in age between its day staff and evening staff. A random sample of 35 staff members is selected from each group. The data are given below. Test the hypothesis that there is no difference in age between the two groups. Use $\alpha = 0.05$ .
$\text { Day Staff }$
$\begin{array}{llllllllllll}22 & 24 & 24 & 23 & 19 & 19 & 23 & 22 & 18 & 21 & 21 & 18 \\18 & 25 & 29 & 24 & 23 & 22 & 22 & 21 & 20 & 20 & 20 & 27 \\17 & 19 & 18 & 21 & 20 & 23 & 26 & 30 & 25 & 21 & 25 &\end{array}$


Evening Staff
$\begin{array} { l l l l l l l l l l l l } 18 & 23 & 25 & 23 & 21 & 21 & 23 & 24 & 27 & 31 & 24 & 20 \\ 20 & 23 & 19 & 25 & 24 & 27 & 23 & 20 & 20 & 21 & 25 & 24 \\ 23 & 28 & 20 & 19 & 23 & 24 & 20 & 27 & 21 & 29 & 30 & \end{array}$