On Aug 23, 2010, at 5:35 PM, Johan Steen wrote:
Thanks for your replies,
but unfortunately none of them seem to help.
I do get p-values in the output, but can't seem to locate them
anywhere in these objects via the str() function.
That is because in the case of Anova.mlm objects ... they aren't there.
I also get very different output using str() than you obtained from
the lm help page
Here's my output:
> A <- factor( rep(1:2,each=3) )
> B <- factor( rep(1:3,times=2) )
> idata <- data.frame(A,B)
> idata
A B
1 1 1
2 1 2
3 1 3
4 2 1
5 2 2
6 2 3
>
> fit <- lm( cbind(a1_b1,a1_b2,a1_b3,a2_b1,a2_b2,a2_b3) ~ sex,
data=Data.wide)
> result <- Anova(fit, type="III", test="Wilks", idata=idata,
idesign=~A*B)
> result
Type III Repeated Measures MANOVA Tests: Wilks test statistic
Df test stat approx F num Df den Df Pr(>F)
(Intercept) 1 0.02863 610.81 1 18 2.425e-15
sex 1 0.76040 5.67 1 18 0.02849
A 1 0.91390 1.70 1 18 0.20925
sex:A 1 0.99998 0.00 1 18 0.98536
B 1 0.26946 23.05 2 17 1.443e-05
sex:B 1 0.98394 0.14 2 17 0.87140
A:B 1 0.27478 22.43 2 17 1.704e-05
sex:A:B 1 0.98428 0.14 2 17 0.87397
Remember I suggested looking for print methods? methods(print)
produces a print.Anova.mlm citation. The above output is produced by
that function which is not visible unless you do:
> getAnywhere(print.Anova.mlm)
A single object matching ‘print.Anova.mlm’ was found
It was found in the following places
registered S3 method for print from namespace car
namespace:car
with value
function (x, ...)
{
test <- x$test
repeated <- x$repeated
ntests <- length(x$terms)
tests <- matrix(NA, ntests, 4)
if (!repeated)
SSPE.qr <- qr(x$SSPE)
for (term in 1:ntests) {
eigs <- Re(eigen(qr.coef(if (repeated) qr(x$SSPE[[term]])
else SSPE.qr,
x$SSP[[term]]), symmetric = FALSE)$values)
tests[term, 1:4] <- switch(test, Pillai = stats:::Pillai(eigs,
x$df[term], x$error.df), Wilks = stats:::Wilks(eigs,
x$df[term], x$error.df), `Hotelling-Lawley` =
stats:::HL(eigs,
x$df[term], x$error.df), Roy = stats:::Roy(eigs,
x$df[term], x$error.df))
}
ok <- tests[, 2] >= 0 & tests[, 3] > 0 & tests[, 4] > 0
ok <- !is.na(ok) & ok
tests <- cbind(x$df, tests, pf(tests[ok, 2], tests[ok, 3],
tests[ok, 4], lower.tail = FALSE))
rownames(tests) <- x$terms
colnames(tests) <- c("Df", "test stat", "approx F", "num Df",
"den Df", "Pr(>F)")
tests <- structure(as.data.frame(tests), heading = paste("\nType ",
x$type, if (repeated)
" Repeated Measures", " MANOVA Tests: ", test, " test
statistic",
sep = ""), class = c("anova", "data.frame"))
print(tests)
invisible(x)
}
<environment: namespace:car>
Notice that after printing "tests", those results are basically
thrown away, and the function invisibly returns its argument. Hacking
that function would be simple matter if you wanted to build a list of
results.
> summary(result)
snipped long and uninformative output.
David Winsemius, MD
West Hartford, CT
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