In a box plot, which statistic represents the middle value of the data?

• A. Mean
• B. Median
• C. Minimum
• D. Maximum

Answer: (B)

In a box plot, the middle value of the data when the numbers are ordered from smallest to largest is the median. The line inside the box marks this median, splitting the data into two halves. This is part of the five-number summary shown in a box plot: minimum, first quartile, median, third quartile, and maximum. If there are an odd number of data points, the median is the exact middle value; if there are an even number, it’s the average of the two middle values. While the mean is another measure of center, it isn’t the value shown by the central line in a standard box plot. The minimum and maximum are the ends of the whiskers, not the central value. For example, with data 1, 3, 5, 7, 9, the median is 5, so the box plot would have a line at 5.