A Sociologist Wants to Determine If the Life Expectancy of People

Multiple Choice

A sociologist wants to determine if the life expectancy of people in Africa is less than the expectancy of people in Asia. The data obtained is shown in the table below.
$\begin{array}{ll}\hline \text { Africa } & \text { Asia } \\\hline \overline{X_{1}}=63.3 \mathrm{yr} . & \bar{X}_{2}=65.2 \mathrm{yr} . \\\sigma_{1}=9.1 \mathrm{yr} . & \sigma_{2}=7.3 \mathrm{yr} . \\n_{1}=120 & n_{2}=150 \\\hline\end{array}$

Calculate the critical value. Use $\alpha = 0.05$ .

A) -2.58
B) -2.33
C) -1.65
D) -1.96