Means, Variance, and Standard Deviation

What is a distribution?

What values a variable takes and how often / how data is spread out

CSOCS Framework

Use this to describe a quantitative distribution. It stands for Context, Shape, Outliers, Center, and Spread.

Mean (average)

This is the sum of all data values divided by the number of data points.

Median

The middle value of a dataset when ordered from smallest to largest.

Variance (s^2)

The average squared distance from the mean.

Standard Deviation (s)

This is the square root of the variance, which puts the measure of spread in the same units as the original data.

What is a percentile?

It's a value below which a given percentage of observations falls.

How do you calculate a percentile?

Use the formula: L=100p​∗n. If the result is a whole number, you average the values at position L and L+1. If it's not a whole number, you round up to the next whole number to find the position.