The class answered the statistical question “How many books did each student in your class read this year?”: a statistical question because the answers vary from student to student. Each observation is a book count, measured in books.

The same values are shown three ways on one number line: a dot plot, a histogram (equal-width bins), and a box plot built from the five-number summary: minimum, Q1, median, Q3, maximum.

The panel reports how many observations there are, and the measures of center (mean, median) and spread (range, interquartile range, mean absolute deviation).

Load the Outlier sample and drag the far-out point. The mean marker follows it, while the median barely moves: whether the mean or the median better describes a typical student depends on the shape of the distribution.