Math
posted by Sue .
Can someone explain what to do for the following question.
What percentage of a normal distribution is greater than the mean? Give your answer correct to the nearest percent.
What formula is used? Because I have to find also 1 standard deviation of the mean and what percentage is greater than a value that is 1 standard deviation below the mean? My book does not explain this very good...

Your Z table makes it clear that the mean is right in the middle. That is 50% is greater, 50% is less.
Take a visit to
http://davidmlane.com/hyperstat/z_table.html
and you can play around with these ideas.