id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-022879-j6cecioe	Fager, Edward W.	Determination and Analysis of Recurrent Groups	1957-10-01		.txt	text/plain	6287	279	57	Transformation of the data or the use of rank correlation could overcome this difficulty, but any method which involves a measure of abundance may, in certain cases, not lead to the desired results : two species may always occur together and never separately and yet, unless there is a nearly constant relation between the relative numbers of individuals of the two species, a correlation coefficient will indicate no relationship even though they are a constant part of each other's biological environment. The following example shows that it is not a satisfactory criterion for grouping if the groups are to be composed of species which form a nearly constant part of each other's biological environment: Species 1 and 2 show no evidence of association when examined by Cole's method and yet they nearly always occur together-over 80% of the occurrences of each are in company with the other -and should be considered together in any grouping based on this set of samples.	./cache/cord-022879-j6cecioe.txt	./txt/cord-022879-j6cecioe.txt