(a) _Reliability of Budgets. Tests._
As a test of the reliability of the budget returns several sets were
taken at random and were arranged in two groups having a common factor
of approximately equal numbers of persons and equal total income. It was
found on addition that the proportion of total expenditure spent on each
description of food, clothing, etc., was approximately the same in each
family and income group. Thus we treated the first 30 budgets from
households with small and large incomes in this manner, dividing them so
that each lot of 15 would have about the same number of persons and the
same income. The selection was made without any reference whatever to
expenditure, and the following were the results:--