Hi all,
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
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