Re: Is my model right for survival rate?

From: <arthur.gilmour_at_DPI.NSW.GOV.AU>
Date: Fri, 14 Sep 2007 14:16:23 +1000

Dear luan sheng

I am the beginner of asreml. I am estimating the variance of survival
rate which is from the challenge test data of turbot. Turbot is one of
marine fishies.
this is my model:
survival !bin !probit !wt=0 ~ mu !r animal fullsib 0.2
Is the model right for this analysis? which is right for survival rate
logit or probit link function?
The format of data file is just like this:
animal Sire Dam fullsib survival (binary,0 for death, 1 for survival)
20070028 2006041 20060159 3 0
20070029 2006041 20060159 3 0
20070030 2006041 20060159 3 0
20070031 2006041 20060159 3 0

I strongly suggest you also fit a sire model, and compare the results,
as the animal model can give biassed estimates of the variance with
binomial data.
In this case, you appear to have large families so it might be fine.

survival !bin !probit !wt=0 ~ mu !r Sire fullsib 0.2

I cannot tell from the data whether Sire and Dam provide the same grouping
of records
(i.e. you only have full sib families). If you have half sib families,
then also\
fit Dam.

As a new user, you should try several forms of the models to get a feel
for how models compare. e.g. You can also fit the models as if the
traits were
normal. Your model is simple, and appears to have an incidence around 50%
so a Normal analysis should be consistent with the binary analysis.

For binary data, you can omit the '!wt=0' qualifier as 0 is the default

May Jesus Christ be gracious to you,

Arthur Gilmour, His servant .

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Received on Tue Sep 14 2007 - 14:16:23 EST

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