Two questions:

1. Let X be the mean of a random sample of size 12 from the uniform distribution on the interval (0, 1). Approximate P(1/2 < X < 2/3)

2. Let X be the mean of a random sample of size 36 from an exponential distribution with mean 3. Approximate P(2.5 < X < 4)

The first one I don't understand how to get the expectation and the variance.

The second one I have no idea because it's exponential.

Thanks for the help.