hessian positive definite

  1. R

    unable to make model Hessian positive definite - help!

    Hello all, My first time posting here, and really hoping that someone can help me out! I have data from a repeated measures experiment in which the time points were not evenly spaced + some missing data from individual animals, so I am using proc mixed and attempting to find the appropriate...
  2. R

    repeated measures + SAS + covariance structure

    Hello, My first time posting here, and really hoping that someone can help me out! I have data from a repeated measures experiment in which the time points were not evenly spaced + some missing data from individual animals, so I am using proc mixed and attempting to find the appropriate...