The Application of the Chi-Squared Test
Robin L. Plackett · The Mathematical Gazette · 1971
Suppose that we open a telephone directory and select any column which consists entirely of personal names. The last digit of each telephone number would seem to have no preferred value. For example, the middle column on p. 417 of the 1970 Newcastle upon Tyne directory contains 109 names, and the frequencies for 0,1,…, 9 are as follows.