Comparing box plots

A box plot is a graphical representation of a data set that shows its minimum, first quartile, median, third quartile, and maximum.

The range represents the difference between the highest and lowest values in a data set.

The IQR is calculated by subtracting the first quartile (Q1) from the third quartile (Q3).

The median is the middle value when the data set is ordered from least to greatest.

Add the two middle numbers and divide by two.

A wider box indicates a greater spread of the middle 50% of the data.

A box plot is used to visually summarize the distribution of a data set and to identify outliers.

The line inside the box represents the median of the data set.

An outlier is a value that is significantly higher or lower than the other values in the data set.

You can compare the lengths of the boxes and the whiskers; a longer box or whisker indicates a greater spread.