Statistics for Business: Decision Making and Analysis, 3rd Edition

$$\begin{array}{c}\frac{{\displaystyle \mathrm{...\; 40}}}{}+\frac{{\left({\displaystyle 100-60}\right)}^2}{{\displaystyle 60}}+\frac{{\left({\displaystyle 80-40}\right)}^2}{{\displaystyle 40}}+\frac{{\left({\displaystyle 20-60}\right)}^2}{{\displaystyle 60}}\hfill \\ =40+26.67+40+26.67\hfill \\ =133.33\hfill \end{array}$$

Cramer’s V indicates strong association between the variables.

$$V=\sqrt{\frac{133.33}{200}}=0.816$$

The size of Cramer’s V implies that you can almost predict what a person will say if you know whether that person is on the staff or is a student. If you know a person is on the staff, then you know that person thinks it is not okay to share files. Among students, however, you cannot be certain. Most—but not all—favor file sharing.

Checklist: Chi-squared and Cramer’s V.

Chi-squared and Cramer’s V measure association between two categorical variables. Before you use these, verify that your data meet these prerequisites.

• ✓ Contingency table. Make sure that the cells of the table are mutually exclusive ...