GCSE Maths 2025 – 400 Free Practice Questions to Pass the Exam

Box plots are a visual representation of the distribution of a data set and are particularly useful for illustrating two key measures of spread: the range and interquartile range.

The range is the difference between the maximum and minimum values in a data set, providing a measure of how spread out the values are overall. In a box plot, this is visually represented by the "whiskers," which extend from the box to the maximum and minimum data points.

The interquartile range (IQR), on the other hand, is the range of the middle 50% of the data. It is calculated by subtracting the first quartile (Q1) from the third quartile (Q3). The IQR is depicted in the box plot itself, where the box spans from Q1 to Q3, and it gives a clear indication of the central spread of the data, removing the effects of outliers.

The other options do not reflect what a box plot illustrates. The mean and median relate to the center of data distribution rather than the spread. Variance and standard deviation are statistical measures that express spread but are not depicted in box plots. Count and frequency pertain to descriptive statistics of how often data values occur, which is not visualized