Hello, I'm trying to calculate non-parametric probabilities using the np package and having some difficulties. OS is Windows, R version 2.11.1 Here is what I've done so far. library(np) veg <- data.frame(factor(Physiogomy), meanAnnualDepthAve, TP) attach(veg) : for clarification dim(veg) returns 1292 3 fy.x <- npcdens(veg$factor.Physiogomy ~ veg$meanAnnualDepthAve, nmulti=1) # this works, but I haven't found any information explaining what the nmulti=1 term is doing? Does this set the number of levels in the factor? My data actually has 8 types, can I develop this to treat each one in a single function ? veg.eval <- data.frame(Physiogomy = factor('Marl"}, meanAnnualDepthAve seq(min(meanAnnualDepthAve), max(meanAnnualDepthAve)) # This also works, however where does the 4755 records originate str(veg.eval) ' data.frame': 4755 obs of 2 variables $ Physiogomy : factor w / 1 level "Marl" : 1 1 1 1 .... $ meanAnnualDepthAve : num -592, -591 - 590 - 578 because the data frame veg only contains 1292 records the is a mismatch between the 4755 records. Why are so many records produced in the veg.eval statement and how can i constrain it to be consistent with the dimensions of veg ? plot(x, y, type = "l", lty="2", col='red' , xlab = "Mean Annual Depth", ylab="Estimated Prob of Marl") lines(veg.eval$meanAnnualDepthAve, predict(fy.x, newdata=veg.eval), col='blue') I'm following an example I found Here: http://en.wikipedia.org/wiki/Density_estimation Your help is greatly appreciated. Thanks Steve [[alternative HTML version deleted]]