Our correct use of ANCOVA yields acceptable results
Gilmore (2007) argues that the use of ANCOVA in Anstey et al.(2006) is invalid. Based on
quotes in Winer (1971), he claims that covariates cannot be used to adjust interaction terms
involving within-subject variables. Because the within-subject variable in Anstey et al.(2006)
is time, he concludes that the results involving Time× Group interaction coefficient are invalid
and consequently all analyses need to be re-done.
quotes in Winer (1971), he claims that covariates cannot be used to adjust interaction terms
involving within-subject variables. Because the within-subject variable in Anstey et al.(2006)
is time, he concludes that the results involving Time× Group interaction coefficient are invalid
and consequently all analyses need to be re-done.
