Re: some help with a covariate please

Matt <matt.lewis2@xxxxxxxxx> wrote in news:dd12b9e9-d957-47c8-9fc6-
a04de51f9fee@xxxxxxxxxxxxxxxxxxxxxxxxxxx:


This is a cross post from the spss forum, but did not capture the
public's imagination!

I am doing some exploratory analysis to see if a task we are using
in a within subjects design is affected by age.

Participants have completed the task 5 times in close succession
giving T1, T2, T3, T4, T5.

Using repeated measures GLM in SPSS with no covariate the main
effect is significant.

if age is added into the analysis as a covariate this difference is
no longer significant which suggests that age plays some role.

Is there any subsequent analysis I can do to further explore this
role, or some option in SPSS which will show this?


Presumably you can plot means over the 5 tests for the whole group. I
am assuming you will see some learning.

Now break your population into 3 equal sized age groups and repeat the
plot within groups. What happens?

--
David Winsemius
.

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