Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores. Use the proportions between Z and mean and multiply by 400.
In a set of 400 values, the mean is 121 and the standard deviation is 14. Estimate how many values fall in between each interval
a) 107 - 135
b)93 - 149
c) 79 - 163
1 answer