Hybridization Between Rana Pipiens From Vermont and Eastern Mexico.

1 Wilson, Edwin B., Bennett, Constance, Allen, Margaret, and Worcester, Jane, "Measles and Scarlet Fever in Providence, R. I., 1929-1934, with Respect to Age and Size of Family," Proc. Amer. Philos. Soc., Philadelphia, 80, 357-476 (1939). See particularly pp. 441-453. 2 Such a method has been used in economic statistics to discuss connectivity of fluctuations. See Wilson, Edwin B., "The Periodogram of American Business Activity," Quarterly Journal of Economics, May 1934, pp. 375-417, especially pp. 386, 409, 415. 3 Yule, G. U., Introduction to the Theory of Statistics, or new edition by G. U. Yule and M. G. Kendall. 4 In the symmetrical case where (A,B) = (aB) and PA = PB = s, the condition PAB/S > /PA that "the chance of B if A " exceeds "the chance of A " is equivalent to the statement that the 4-fold table be positively associated. 6 One may use as notation subscripts-those preceding the dot designating the group of whicli the probability is specified, those following the dot designating the attributes considered as granted.