testing fixed effects
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testing fixed effects

Good morning all (or evening depending upon which hemisphere you reside),

Unfortunately I am in the position of having to test the significance of my
fixed effects. I am aware that this is not a simple task. I have been warned
that the Wald statistic is only asymptotically distributed as a Chi square
if all the variance components except the error is know (a situation that I
am not in). The Questions chapter in the ASREML manual briefly addresses
this question but with no great conviction. Welhamn and Thompson (1997) have
also discussed this problem and describe a likelihood ratio test for fixed
effects but I am unsure whether I can manipulate ASREML to do this.

So are there better ways than the Wald statistic to test for the
significance of fixed effects within a mixed model setting while still being
able to use ASREML?


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