Counts vs Density

Both columns show the same 500 observations with two different binning schemes. With equal-width bins, counts and density have the same shape. With variable-width bins, raw counts favor wider intervals and can distort the visual comparison.

With equal-width bins, taller bars indicate a greater probability of falling within that interval. When bin widths vary, height alone is not enough: probability is represented by the bar’s area, calculated as density multiplied by bin width.

Note that variable-width bins are ideal for unbalanced distributions and outliers, as shown in Histograms - Khiops.

Reading variable-width histograms

Question	Use	What to compare
How many observations?	Counts (density=False)	Bar heights
What fraction of observations?	Counts divided by \(N\), or density times bin width	Bar areas
Where are values concentrated?	Density (density=True, the Khisto default)	Bar heights