Mean, Median, and Mode

Box-and-whisker plot

A box-and-whisker plot is a method of displaying data that uses quartiles to form the center box and the maximum and minimum values to form the whiskers.

Measures of Central Tendency

The mean, the median, and the mode are single, central values that help describe a set of data. They are called measures of central tendency.

Median

The median is the middle value in a data set. If the data set contains an even number of values, the median is the mean of the two middle values.

Quartiles

Quartiles are values that separate a finite data set into four equal parts. The second quartile (Q2) is the median of the data. The first and third quartiles (Q1 and Q3) are the medians of the lower half and upper half of the data, respectively.

Bimodal

The mode is the most frequently occurring value (or values) in a set of data.

Mode

The mode is the most frequently occurring value (or values) in a set of data.

Mean

The sum of the data values divided by the number of data values is the mean.

Percentile

A percentile is a value that divides the range of a data set into two parts such that the part below the percentile contains a given percent of the data.

Outlier

An outlier is an item of data with a substantially different value from the rest of the items in the data set.