Yule's Q
Phi

Two Nominal Variables; both are two-point scales and you want to measure covariation

In this case, Yule's Q is equivalent to Goodman and Kruskal's gamma, and phi is equivalent to Pearson's product moment r.  Use TABLES for Yule's Q, and Phi.  In general, Q will be higher in absolute value than phi because Q ignores pairs of cases which fall in the same category on one or both of the variables.

Statistical tests for covariation include Fisher's exact test, and the Pearson chi-square.  TABLES computes the probability of Phi.  You can use TABLES to compute the Fisher Exact Test (See McNemar, 1969, p. 227.)