Hi,
Note: Bell shaped Curve showing placement of z = 0, z = ±1, 2, 3
Left or Right of z = 0 being 50% of the area under the standard normal curve...
The area under a normal curve = 1
As to: A set of data is normally distributed with a mean of 85 and SD of 4.59
x = 90
z = (90-85)/4.59 = 1.089
Exel function NORMSDIST(1.089) = .862 , 86.2% to the left and 13.8% to the right
As:a normal distribution with mu = 25 and sigma = 9, if z = -2,
then z = (x -25)/9 = -2, and x = -18 + 25 = 7