7.1 Introduction

\(\chi^2\) tests (‘ki-squared tests’) are used to analyse data where each unit of analysis has two qualitative variables measured (or observed) about it. This type of data can be compiled into a two-way table of counts.

Consider data (Gammon et al. 2012) used in Exercise 31.16 of the textbook (Table 7.1).

Two qualitative variables being measured on each individual:

Whether the person is vegetarian (or not);
Whether the person is B12 deficient (or not);

So SPSS will have two columns: one for each variable.

The data file (B12-Long.sav) can be downloaded in Sect. 10.

You can download the data, and follow the instructions.

TABLE 7.1: The number of vegetarian and non-vegetarian women who are (and are not) B12 deficient
	B12 deficient	Not B12 deficient	Total
Vegetarians	8	26	34
Non-vegetarians	8	82	90
Total	16	108	124

References

Gammon, Cheryl S., Pamela R. von Hurst, Joan Coad, Rozanne Kruger, and Welma Stonehouse. 2012. “Vegetarianism, Vitamin B12, and Insulin Resistance in a Group of Predominately Overweight/Obese South Africian Women.” Nutrition 28: 20–24.