search for: msamp

I am trying to calculate monthly means by year of phosphates and nitrates from a multi year data set. Can anybody help me out with the most effective way to do this? My data looks like this: Collection_Date                   Test.Name              Value 2000-01-24 17:00:00            Phosphate               0.108 2000-01-24 17:00:00            Nitrate                     0.037 2001-11-12

I'm using the fwdmsa package to identify deviant cases in a Mokken scale analysis. I've run into a problem. When I use scales comprising a few items, iI tend to get an error: Error in y[order(res[-msamp])][1:(length(samp) + 1 - length(msamp))] : only 0's may be mixed with negative subscripts I understand that the error is triggered when the algorithm is fetching cases to enter into the next step of the forward search. I don't understand what I can do to remedy this error. The data are...

Hi, I am having trouble understanding how to approach a simulation: I have a sample of n=250 from a population of N=2,000 individuals, and I would like to use either permutation test or bootstrap to test whether this particular sample is significantly different from the values of any other random samples of the same population. I thought I needed to take random samples (but I am not sure how