SOLUTION: The lengths of boards are normally distributed with a mean of 3.9m and a standard deviation of 1.8m. Seventy-five percent of the boards are less than what amount? HELP, HELP -

Algebra ->  Probability-and-statistics -> SOLUTION: The lengths of boards are normally distributed with a mean of 3.9m and a standard deviation of 1.8m. Seventy-five percent of the boards are less than what amount? HELP, HELP -       Log On


   

Question 955029: The lengths of boards are normally distributed with a mean of 3.9m and a standard deviation of 1.8m. Seventy-five percent of the boards are less than what amount?
HELP, HELP - I'M DROWNING!!!
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Find the z score when P=0.75.
The corresponding z score is z=0.674.
0.674=%28x-3.9%29%2F1.8
x-3.9=1.2132
x=5.11m