VarP (Variance of a Population)

Variance is a measure of how spread out a set of values is.

VarP returns this measure based on an entire population. This is a group-value function.

Syntax

VarP <FactID>(Argument)

Where:

• Argument is an attribute, fact, or metric representing a list of numbers.
• FactID is a parameter that forces a calculation to take place on a fact table that contains the selected fact.

Expression

Usage Notes

For this function, arguments relate to an entire population as opposed to a population sample.

Example

Variance is calculated as the average squared deviation of each number from its mean. This example creates a report in which the variance of the units sold in the subcategories within a category is calculated with the assumption that the data provided represents the entire population.

Compare this example report to the example for variance of a sample to see the different values returned when calculating for a population as opposed to a sample.

The report includes the attributes Category and Subcategory, and the metrics Units Sold and VarP by Category. A report filter limits the categories displayed to Books and Movies. The VarP by Category metric is defined as follows:

VarP([Units Sold]) {Category, ~}