
Probability Problem Help
For a standardized psychology examination intended for psychology majors, the historical data show that scores have a mean of http://www.aleks.com/alekscgi/x/math2htgif.exe/NM?613 and a standard deviation of http://www.aleks.com/alekscgi/x/math2htgif.exe/NM?243. The grading process of this year's exam has just begun. The average score of the http://www.aleks.com/alekscgi/x/math2htgif.exe/NM?73 exams graded so far is http://www.aleks.com/alekscgi/x/math2htgif.exe/NM?673. What is the probability that a sample of http://www.aleks.com/alekscgi/x/math2htgif.exe/NM?73 exams will have a mean score of http://www.aleks.com/alekscgi/x/math2htgif.exe/NM?673 or more if the exam scores follow the same distribution as in the past?
Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.

Because you are looking at the probability of the mean you should consider $\displaystyle P(\bar{X}\geq 540) = P\left(Z\geq\frac{\bar{X}\mu}{\frac{\sigma}{\sqrt{n}}}\right)$
