Conditional Relative Frequency

A conditional relative frequency is the ratio of a joint frequency to either of its two corresponding marginal frequencies. Alternatively, it can be calculated using joint and marginal relative frequencies. As an example, the following data will be used.

Referring to the column totals, the left column of joint frequencies should be divided by 67 and the right column by 33. Furthermore, since the column totals are used, the sum of the conditional relative frequencies of each column is 1.

The resulting two-way frequency table can be interpreted to obtain the following information.

• Out of all the participants with a driver's license, about 64 % of them own a car.
• Out of all the participants with a driver's license, about 36 % of them do not own a car.
• Out of all the participants without a driver's license, about 12 % of them own a car.
• Out of all the participants without a driver's license, about 88 % of them do not own a car.