Calculate: Variance

The fourth measure of dispersion is variance. Variance is the Sum of Squares divided by N

Variance of a population is always SS divided by N; regardless whether it is a large population or a small population.

Variance of a large sample (where N is equal to or larger than 30) is calculated like a population. Divide SS by N.

If the sample is small (less than 30), adjust for the small sample size by dividing SS by N-1.

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Day 3: Dispersion
A Bit More About Dispersion
Even More About Dispersion
Range
MAD
Sum of Squares
Variance
Standard Deviation
How To Calculate
Range
MAD
Sum of Squares
Variance
Standard Deviation
Formulas For Dispersion
Practice Problems
More Practice Problems
Basic Facts About Dispersion
Vocabulary
Quiz 3
Summary