I would like to solve the equation is is the sum from k = i to N of choose(N,k) * MR ^ k * (1 - MR) ^ (N - k) - 0.50 = 0
I want to solve for MR. This seems like a non-linear equation to me. But I am having a hard time writing the function that implements the above. I could use 'for(...) as a brute force appoarch but I would like a more "elegant" solution. The variables 'N' and 'i' are basically constant so the function has to take these from some kind of global space. So if I take t brute force apporach I came up with: f <- function(MR) { k <- i:N return sum(choose(N,k) * MR ^ k * (1 - MR) ^ (N - k)) - 0.5 } Does this seem like a reasonable implemetation? How are 'N' and 'i' declare as "global"? For each equation N and I are constant but I want to be able to modify them. In other words solve the equantion after setting N to 6 and i to 5 then again after setting i to 4. The next question is regarding which 'R' function would be best suited to solving this equation? I looked at 'nls' but that seems to take data as an input. I want to solve the equation. What other options do I have? There must be an 'R' function to solve a non-linear equation. I did help.search("non-linear") and the closest match was nlm. But nlm minimizes the function rather than solving it. Ideas? Thank you. Kevin ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.