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## Homework Statement

Find P(X>130) where

P(X > 130) = 1 − Φ( (130 − µ)/σ )

## Homework Equations

Φ is the normal distribution density function:

http://en.wikipedia.org/wiki/Normal_distribution

## The Attempt at a Solution

This is pretty simple to use in R if one knew how to. I get a ghastly incorrect answer. Dividing the number of items above 130 by the total number of items yields 0.022, and the above yields something like 0.4e-5 if I use the mean and stdev from the data set. So, what µ and σ are they? They can't be the ones from the data set.

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