Re: logistic regression question

On Feb 1, 11:03 am, amorphia <spam.onto...@xxxxxxxxx> wrote:
Hi all,

I have an experimental design where subjects make a sequence of simple
binary choices A or B. I would like to test the hypothesis that
initially in the sequence subjects tend to choose A, but this bias
degrades to random (or perhaps a bias to B) as the sequence
progresses.

Initially I thought that maybe I could do a simple binary logistic
regression, with sequence position as the only covariate. But now I
think that this is probably invalid, because this would assume that
choices at sequence position t+1 are independent of choices at
sequence t. This assumption is plainly false because the choices are
made by the same individuals who may make runs of the same choice.

Can I solve this problem by including individual as a factor in the
model perhaps? Or is a more complicated solution necessary?

Thanks!

Ben


How many choices are subjects making? If it is a large enough number,
a relatively easy way to see graphically if your hypothesis is
supported would be to create convenient sized bins, and plot the
proportion of A-responses in each bin. Depending on how that looks,
maybe something as simple as repeated measures ANOVA (with trend
analysis) would work.

--
Bruce Weaver
bweaver@xxxxxxxxxxxx
www.angelfire.com/wv/bwhomedir
"When all else fails, RTFM."
.

Relevant Pages

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