On 28 Feb 2001 09:24:55 -0800, [EMAIL PROTECTED] (Mike Granaas) wrote:
>
> I have a student coming in later to talk about a regression problem.
> Based on what he's told me so far he is going to be using predicting
> inter-response intervals to predict inter-stimulus intervals (or vice
> versa).
- Is it just me, or is that sentence hard to parse?
" ... he is going to be using
predicting inter-response intervals
to predict inter-stimulus intervals (or vice versa)."
Since I am accustomed to S -> R,
I assume the 'vice-versa' must be the case; it leaves me with
"Intervals between stimuli that predict, predicting <sic> intervals
between responses."
Can I drop the word 'predicting' that seems (to me) accidental?
Well, it seems to me that an 'interval' can be a stimulus or
a measure of response, but when the problem keeps that
terminology, it (further) suggests to me that data are
collected as a time-series.
- If so, Time-series has to be incorporated, from the start.
>
> What bothers me is that he will be collecting data from multiple trials
> for each subject and then treating the trials as independent replicates.
> That is, assuming 10 tials/S and 10 S he will act as if he has 100
> independent data points for calculating a bivariate regression.
>
> Obviously these are not independent data points.
>
> Is the non-independence likely to be severe enough to warrant concern?
>
> If yes, is there some method that will allow him to get the prediction
> equation he wants?
- Can he do a prediction equation on one person?
If there's a parameter for a person, then
he has 10 people, each of whom yields a parameter value.
A test, of sorts, might be possible on the scores for one person.
But the generalization is tested using the 10 scores,
comparing those parameter values to some null.
His power-of-analysis will be much better if he can define
his hypotheses from the start, instead of trying to let a
pattern 'emerge from the data' across the 10 consecutive trials.
--
RIch Ulrich, [EMAIL PROTECTED]
http://www.pitt.edu/~wpilib/index.html
=================================================================
Instructions for joining and leaving this list and remarks about
the problem of INAPPROPRIATE MESSAGES are available at
http://jse.stat.ncsu.edu/
=================================================================
