Statistics & Probability

Quartile

The values that split sorted data into four equal parts. Q1 (25%), Q2 (median, 50%), Q3 (75%).

Definition

Read quartiles from a cumulative frequency graph by drawing horizontal lines at 25%, 50% and 75% of the total and reading off the x-values.

Used in these topics

Related terms

Median

The middle value when the data is sorted in order. For an even count, average the two middle values.

Interquartile range (IQR)

A measure of spread: Q3 − Q1. Less sensitive to outliers than the range.

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