Please consider the following R Script: x = c(1,2,3) y = c(1,2,9) cor(x,y) These three lines will produce, as I expected, the correlation between the variables x and y. However, R is going to assume that the probability that x = 1 is the same as the probability that x = 2. Suppose I know the probability that x = 1 is 0.5 and the probability that x = 2 (or x = 3 ) is 0.25. I believe that would effect the correlation between the variables x and y. How do I tell R about these probabilities? I thank the group in advance for their responses to this post. Bob