Parameters. Every Normal model is defined by its parameters, the mean and the standard deviation. For each model described here, find the missing parameter. As always, start by drawing a picture.

a) m = 45, 4% below 38; s = ?

b) m = 6, 74% above 4; s = ?

c) s = 10, 30% above 55; m = ?

d) s = 6, 90% below 28; m = ?