Leave one-subject cross-validation score for local linear fit
CVlm(Xvec, Yvec, bw, ID, Wt)numeric vectors of data values, Xvec and Yvec must have the same length.
a bandwidth of the Epanechnikov kernel
subject ID of the data value
a weight vector, may be subject-specific. a weight vector or a constant. For longitudinal data, Wt=1/N corresponds to measurement uniform weight and Wt=1/(nni) corresponds subject uniform weight.