Contingency tables
Table 4-4 and Table 4-5 are examples of contingency tables (also called crosstab tables). These are multivariate tabulations of two random variables in which one seeks to prove their dependence or independence.
Here is a classic example:
|
Right-handed |
Left-handed | ||
|---|---|---|---|
|
Male |
43% |
8% |
51% |
|
Female |
45% |
4% |
49% |
|
88% |
12% |
100% |
Table 4-6. Handedness by sex
In this population, 88% are right-handed. But 49% are female, and 45% are both female and right-handed, so 92% (0.45/0.49) of the females are right-handed. So being right-handed is not independent of sex.
