A display in which each bar's HEIGHT is the number of data points in a bin, not a data value. The most misread display on the test: bars of height 3, 5, 8, 4 over values 1, 2, 3, 4 describe twenty data points, not the set 3,5,8,4 — and 4.5 (the median of the heights) and 5 (the mean of the heights) are waiting among the options.