A variable of two populations has a mean of 42 and a standard deviation of 11 for one of the populations and a mean of 51 and a standard deviation of 14 for the other population.

a) For independent samples of sizes 59 and 46, respectively, find the mean and standard deviation of $\overline{x}_1 - \overline{x}_2$.
mean:
standard deviation:

b) Can you conclude that the variable $\overline{x}_1 - \overline{x}_2$ is approximately normally distributed? (Answer yes or no)
answer: