are variable kernels used for the density of the data? why is variable kernel used in regression why are variable kernels used in kernel density estimation what does variable kernel mean why variable kernel widths what is variable kernel used for why is a variable kernel used in local regression why is kernel density estimation not good for regression what is an example of a variable kernel why are variable kernels in local regression useful for kernel density estimation why is kernel density important in local regression what are variable kernel widths for are variable kernels considered kernel density what are variable kernels used for what is a variable kernel used for why are variable kernels usually used what is variable kernel width why are variable kernels not used in density estimation for regression why are variable kernels used in local regression why don't kernels work well for density estimation