# MandysNotes

## What's with the Greek? (4)

Friday, 22 January 2010 00:00

### Mu = Mean

The Greek lowercase letter for "M" (pictured above on the right) is pronounced as "mew."

This symbol represents the mean of a data set.

Friday, 22 January 2010 20:22

### X Bar = Sample Mean

By

X Bar (pictured below under Sample Mean) is simply the mean of a given set of sample values.

As you will notice, "X Bar" is the same as the POPULATION MEAN, merely reexpressed.

Friday, 22 January 2010 19:54

### Lowercase Sigma = Population Standard Deviation

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$\sigma$

This symbol, the lowercase "sigma," represents the POPULATION STANDARD DEVIATION

The formula to calculate the population standard deviation is:

Friday, 22 January 2010 19:48

### Capital Sigma = Sum

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"SIGMA" means the SUM:

The "sum of what?"  The sum of a set of values:

EXAMPLE:

(1 + 2 + 3 + 4 + 5) = 15