I wish to us a repeated measures design to investigate the effects of
two types of exaggeration on the perception of animations. For both
types of animation I would like include a level that leaves the
orginal unchanged. Thus some trials would involve presentaion of
identical animations but be in different cells of the design. I guess
my default approach would be to ignore this fact, except perhaps to
plan to test that there is no difference between the equivalent cells.
However it seems you should be able to take advantage of the repetion
either 1) By not duplicating the trials but using the same data for
both cells of the design thus saving your observer's some trials. I
guess this invalidates the default model of sources of variance 2)
Include duplicate trials, but in some way use the fact they are
equivlaent to give you a better estimate of the variance associated
with the equivalent cells. Not sure how you would do this though.
I hope this is a vaguely interesting question for this group and I
would much appreciate any thoughts/references. I can't believe I am
in a unique situation as no treatment must be a fairly common level to
want in for a variety of variables but it is not something that I have
seen covered. Please note I am not a statistician but a humble
psychologist - please tailor any answers appropriately. This is what
also makes me baulk at trying to implement an explicit model of
sources of variances for this situation though I guess this is what
you may recommend.
Thanks,
Harold
.
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