Question

if x is a normally distributed random variable with amean of 8.00 if the proability for x is less than 9.54 is 0.67, then find the standard deviation of x

Answer 1

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion (.67) and insert its Z score in the equation above to solve for SD.