Posted by arron on .
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

algebra 
PsyDAG,
Z = (scoremean)/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.