Suppose the results for stat 201 in 2014 are normally distributed with mean 160 and

Question

standard deviation 18 . Find the probability that a random sample of size 36 gives a
sample mean value in the following cases

Question : between 120 and 220

p(120 < z < 220)
p(120-160/3 < z < 220-160/ 3)
p(-13.33 < z < 20)
got stuck...

Answer 1

try

http://davidmlane.com/hyperstat/z_table.html