Hi all,
I sent a post out last week, but I forgot to leave my e-mail address
(hrobison@unr.nevada.edu). In case any of you have insights into my question,
I am re-sending my post.
I having trouble specifying MANOVA (in the GUI of S-plus 6.2) that allows the
contrasts I'd like.
I was hoping the MANOVA would let me test for differences among levels of "Pop"
(my X variable with 32 levels) with respect to my repeated measurements for
each "Pop", my Ys ("logk2.k1", "logk3.k1", "logk4.k1", "logk5.k1", "logk6.k1",
"logk7.k1", "logk8.k1", "logk9.k1", "logk10.k1", "logk11.k1"). My Ys were
measured 5 times in each "Pop." The output gives me an overall p-value for
"Pop", but does not give me p-values for the contrasts among my levels of
"Pop."
How do I specify this?
What I did in the S-plus GUI was:
Statisitics -> Multivariate -> MANOVA dialog box
In the "Model" tab of the MANOVA dialog box I specified:
Dataset: group
Formula : cbind(logk2.k1, logk3.k1, logk4.k1, logk5.k1, logk6.k1, logk7.k1,
logk8.k1, logk9.k1, logk10.k1, logk11.k1) ~ Pop
In the "Options" tab of the MANOVA dialog box I specified:
Assign Contrast: Helmert
to Variables: Pop
Contrasts: Pop=contr.helmert
In the "Results" tab of the MANOVA dialog box I specified:
Short Output
ANOVA Table
Testing with "pillai"
Estimated Coefficients
Estimated K Coef. for K-level Factor
Save In: group
Fitted Values
Residuals
The Report gives me:
Call: manova(formula = cbind(logk2.k1, logk3.k1, logk4.k1, logk5.k1, logk6.k1,
logk7.k1, logk8.k1, logk9.k1, logk10.k1, logk11.k1) ~ Pop, data = clusters,
contrasts = list(Pop = contr.helmert), na.action = na.exclude)
Terms:
Pop Residuals
Deg. of Freedom 32 132
Estimated effects are balanced
Analysis of Variance Table:
Df Pillai Trace approx. F num df den df P-value
Pop 32 4.426 3.275 320 1320 0
Residuals 132
Followed by the estimated coefficients for "logk2.k1", "logk3.k1", "logk4.k1",
"logk5.k1", "logk6.k1", "logk7.k1", "logk8.k1", "logk9.k1", "logk10.k1",
"logk11.k1" for each "Pop."
Thank you for your thoughts on this.
Hillary Robison (hrobison@unr.nevada.edu)
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