Definition: A box plot is a data display that uses a number line to show the minimum, first quartile, median, third quartile, and maximum of a data set.
What is a box plot?
A box plot, also called a box-and-whisker plot, shows the five-number summary in one picture. The box spans Q1 to Q3, a line inside marks the median, and the whiskers reach the minimum and maximum.
How do you read it?
Suppose Mathbot’s battery tests give min 12, Q1 20, median 26, Q3 33, max 45 (hours).
- The box covers 20 to 33, so IQR = 13.
- The median 26 splits the data in half.
- The range is 45 – 12 = 33.
Each section, whisker to box to median and beyond, holds about 25 percent of the data.
What does it reveal?
Box length shows spread. If the median is close to Q1, the lower half is packed tightly and the upper half is stretched out.
What is a common misunderstanding?
A longer box does not mean more data. Each quarter holds the same count. A wide section just means those values are more spread out. Also, a box plot does not show individual values.