Histogram
SAT glossary · Math
Definition
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.
Histogram in plain English
A histogram is a bar chart for numerical data, but here's the critical part: the HEIGHT of each bar tells you how many data points fall into that range (called a 'bin') — the height is a COUNT, not an actual data value itself. This is the most commonly misread chart on the whole test: if you see bars of heights 3, 5, 8, and 4 sitting above the labels 1, 2, 3, 4, that describes a data set of TWENTY total points (3+5+8+4=20), not the tiny four-number set 3,5,8,4. Tempting wrong answers often come from treating the bar HEIGHTS themselves as if they were the data — like calculating the median (4.5) or mean (5) of the heights instead of the actual underlying values.
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