3.1 Introduction

\(\chi^2\) tests (ki as in ‘kite’) 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 the textbook (Table 3.1).

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

You can download the data, and follow the instructions.

This data set is available from the textbook as B12 in Appendix A. You can download the data and follow along if you wish.

There are two variables being measured on each individual:

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

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

There are 124 units of analysis, so there are 124 rows.

TABLE 3.1: 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.