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

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Question 377858: The incomes of trainees at a local mill are normally distributed with a mean of $1100 and a standard deviation of $150. What percentage of trainees earn less than $900 a month?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
P%28X++%3C+900%29+=+P%28%28X+-+mu%29%2Fsigma+%3C+%28900+-+1100%29%2F150+=+-1.33%29. Then P(X < 900) = P(Z < -1.33) . The percentage is equal to this probability times 100%. Just use a table of standard normal values to find the probability.