# MandysNotes

Friday, 22 January 2010 23:22

## 68-95-99.7 (Empirical) Rule

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The EMPIRICAL RULE, otherwise known as the 68.26-95.44-99.74 RULE, says the following:

1) 68.26% of all observed data values will fall between ONE standard deviation to the RIGHT or LEFT of the mean.

2) 95.44% of all observed data values will fall between TWO standard deviations to the RIGHT or LEFT of the mean.

3) 99.74% of all observed data values will fall between THREE standard deviations to the RIGHT or LEFT of the mean.

This is what the illustrated version of the Empirical Rule looks like:

EXAMPLE:

If we are told that the mean of our data is 100, and the standard deviation is 10, then we know the following:

1) 68.26% of our data will fall between 90 and 110.

2) 95.44% of our data will fall between 80 and 120.

3) 99.74% of our data will fall between 70 and 130.

Disclaimer: I did not create nor do I own these videos.  I have simply embedded them, courtesy of YouTube.

Read 3292 times Last modified on Saturday, 23 January 2010 04:03