.
I have an experiment where a component is stressed (nominally to the same
Sorry for not being explicit in my description. The component is strecthed
until it reaches a specified stress, the first value, and then held for a 4
hours and the stress at this time measured. Due to experimental constarints
it is not always possible to obtainn this first stress "exactly". The
outcome is the difference between these two stresses. My concern was that
the value of the first stress may have an effect on the difference ae a
covariate or confounding effect, and I wanted to estimate or eliminate this.
Paul
level) and the stress measured a constant time afterwards for 5 different
materials. I wanted to investigate the effect of material on the difference
in stress giving me the simple model:
anova diff system
The problem is that the initial nominal stress is not constant and may have
en effect on diff.
How can do I formulate this model? I tried anova diff f1, continuous(f1)
but f1 now enters the model as a both a main factor and a component of
diff.
Are you measuring stress on two or more occasions, or just the once?
It's also hard to understand exactly what you mean when you say the stress
was to the same level in the first sentence, but then you say it's not
constant later on.
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