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## #1 2005-09-19 11:36:22

april64
Member
Registered: 2005-09-19
Posts: 1

### Statistics

I am having trouble trying to solve this equation.

Batting averages of major league baseball players are thought to possess a mound-shaped symmetric distrution with a mean of .260 and a standard deviation of .03.  Find the proportion of major league baseball players who have a batting average that exceeds .230.

Thanks!

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## #2 2005-09-19 20:56:47

MathsIsFun
Registered: 2005-01-21
Posts: 7,664

### Re: Statistics

If you look here you can see what that "mound shape" looks like

Now,  0.230 is just 1 Standard Deviation from 0.260 (0.230 + 1×0.03 = 0.260), and when you look up the table you find 1 Standard Deviation = 0.3413, this means that 34.13% of the population are between 0.230 and 0.260, now 50% are above the mean of 0.260, so 84.13% (34.13%+50%) are above 0.230.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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