Box plots

Definition

A box plot, also known as a box-and-whisker plot, is a graphical representation of the distribution of a dataset that displays its minimum, first quartile (Q1), median, third quartile (Q3), and maximum. It is useful for identifying outliers and understanding the spread and skewness of the data.

5 Must Know Facts For Your Next Test

1. The box in a box plot represents the interquartile range (IQR), which contains the middle 50% of the data.
2. The line inside the box indicates the median value of the dataset.
3. Whiskers extend from Q1 to the minimum value and from Q3 to the maximum value, excluding outliers.
4. Outliers are typically plotted as individual points beyond the whiskers and can be identified using 1.5 * IQR rule.
5. Box plots can display differences between distributions by comparing multiple boxes side-by-side.

Review Questions

• What does the interquartile range (IQR) represent in a box plot?
• How are outliers identified and represented in a box plot?
• What information does a box plot provide about data distribution?

Related terms

Interquartile Range (IQR):

The range between the first quartile (Q1) and third quartile (Q3), representing the middle 50% of data.

Median:

The middle value of an ordered dataset, splitting it into two equal halves.

Outlier:

A data point that lies significantly outside the typical range of values in a dataset.