# What is the variance of {-13, 10, 8, -3, 6, 12, 7}?

##### 1 Answer

Dec 18, 2015

Depending upon whether the given data is to be taken as the entire population (all values) or a sample from some larger population:

Population variance

Sample variance

#### Explanation:

This can be determined using standard built-in functions of a scientific calculator or a spread sheet (as below):

...or it may be calculated in steps as:

- Determine the
**sum of the data values** - Divide the
**sum of the data values**by the**number of data values**to obtain the**mean** - For each data value subtract the
**mean* from the data value to obtain the**deviation**from the**mean** - Determine the sum of the
**deviations**of the data values from the mean.

For population variance:

- Divide the
**sum of the deviations**by the**number of data values* to obtain the**population variance**.

For sample variance

- Divide the
**sum of the deviations**by**1 less than the number of data values**to obtain the**sample variance**