Bivariate Frequency Distribution

Everything so far dealt with one variable at a time (a univariate distribution). But a sample often records two pieces of information per unit — for example, from 20 firms both their sales and their advertisement expenditure. Such paired data are summarised in a bivariate frequency distribution: the frequency distribution of two variables together.

One variable's classes run across the columns and the other's across the rows; each cell shows how many units fall into that particular row-and-column combination. In the table below, sales (Rs lakh) form the columns and advertisement expenditure (Rs thousand) the rows for 20 firms:

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