Distribution of a Sample Mean has what Standard Deviation?
After that, it's just a z-score lookup.
Lemmings have a mean body weight of 63.5 grams with a standard deviation of 12.2 grams. If weights are distributed normally, what is the probability that a random sample of 15 lemmings will have an average body weight of 54 grams or less?
I'm not exactly sure what to do.
Can I calculate this with my TI?