The incomes of trainees at a local mill are normally distributed with a mean of $1100 and a standard deviation $150. What percentage of trainees earn less than $900 a month?

Answer 1

great website here
http://davidmlane.com/hyperstat/z_table.html
Just enter you data , and use the "below" button.

Answer 2

n P(X < 900) = P(Z < -1.33).
in the negative z score table -1.33 will be .0918, we move the decimal point to places so the answer will be 9.18%.