Two Independent Samples of Sizes 30 and 40 Are Randomly $\mu$

Short Answer

Two independent samples of sizes 30 and 40 are randomly selected from two populations to test the difference between the population means, µ $\mu$ ₂ - µ $\mu$ _1, where the population variances are unknown. Which of the following best describes the sampling distribution of the sample mean difference $\bar { x } _ { 1 } - \bar { x } _ { 2 }$ ? $\begin{array}{|l|l|}\hline \text { A. } & \text { Normal. } \\\hline \text { B. } & t \text {-distributed with } 68 \text { degrees of freedom. } \\\hline \text { C. } & \text { Approximately normal. } \\\hline \text { D. } & \text { None of these choices are correct. } \\\hline\end{array}$