On Aug 27, 2012, at 6:37 AM, Jean V Adams wrote:
Not sure why that is. You can always use manova() to get the
multivariate
summary statistics and then use individual models to get predictions
for
each response. For example,
mydata <- data.frame(y1=rnorm(50), y2=rnorm(50), x1=rnorm(50),
x2=rnorm(50), x3=rnorm(50))
myfit <- manova(cbind(y1, y2) ~ x1 + x2 + x3, data=mydata)
summary(myfit)
myfit1 <- lm(y1 ~ x1 + x2 + x3, data=mydata)
myfit2 <- lm(y1 ~ x1 + x2 + x3, data=mydata)
I'm guessing this was supposed to be:
myfit2 <- lm(y2 ~ x1 + x2 + x3, data=mydata)
predict(myfit1, se.fit=TRUE)
predict(myfit2, se.fit=TRUE)
I suppose it is possible that what was desired were the standard
errors around the fitted mean estimates (which I think is what this
would deliver), but what was asked were for "standard deviations". I
admit to being puzzled that `manova` was being thought of as a method,
since the sample or population standard deviations should be derived
from three applications of `tapply`. I think BruitishFruit should tell
us what he means by "... don't get the standard deviation values" in
sufficient detail that we get an unambiguous description what
"standard deviations" are being requested. (Or he can pose a small
test case with the "correct answer".)
Jean
BrutishFruit <brutishfr...@hotmail.com> wrote on 08/25/2012 04:09:04
PM:
Hi,
I have problem getting the standard deviation from the manova output.
I have used the manova function: myfit <- manova(cbind(y1,
y2)
~ x1
+ x2 + x3, data=mydata) .
I tried to get the predicted values and their standard deviation by
using:
predict(myfit, type="response", se.fit=TRUE)
But the problem is that I don't get the standard deviation values, I
only
get the predicted values for y1 and y2.
But if I type: predict*.lm*(myfit, type="response", se.fit=TRUE)
I get the predicted values and standard deviation, but only for y1
(and
nothing from y2...).
//BF
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