On May 14, 2011, at 11:23 AM, Eli Kamara wrote:
Hello,
I'm a new user to R so apologies if this is a basic question, but
after scouring the web on information for summary.formula, I still
am searching for an answer.
I made a function to analyze my data - I have a categorical variable
and three continuous variables. I am analyzing my continuous
variables on the basis of my categorical variables.
radioanal <- function(a)
{
#Educational status first - pulling variables from my database.
categorical is 13 = Edu. numerical is 48=Kyph, 50=Vert, 53=HL.
a1= a[,c(13,48,50,53)]
#make sure they are in numeric form
a2= transform(a1, Kyph=as.numeric(as.character(Kyph)),
Vert=as.numeric(as.character(Vert)), HL=as.numeric(as.character(HL)))
#see boxplots of the individual variables
boxplot(a2$Kyph~a2$Edu, main="Education vs Kyphosis angle",
xlab="Education", ylab="Kyphosis angle")
boxplot(a2$Vert~a2$Edu, main="Education vs # of vertebrae affected",
xlab="Education", ylab="#of vertebrae affected")
boxplot(a2$HL~a2$Edu, main="Education vs %HL",
xlab="Education", ylab="%HL")
#see distribution of data
d=summary.formula(a2$Edu~a2$Kyph+a2$HL+a2$Vert, method="reverse",
overall=T, continuous=5, add=TRUE, test=T)
I noticed that you were addressing the columns individually. That
rather defeats the strategy of passing a data argument to a function
and using only the column names in the formula. It often causes
strange errors in model calls and I wouldn be surprised if you got
better results with something like:
d=summary.formula( Edu~ Kyph+ HL+ Vert, data=a2, method="reverse",
overall=T, continuous=5, add=TRUE, test=T)
--
David
#perform MANOVA
a3=manova(cbind(Kyph, Vert, HL)~as.factor(Edu), data=a2)
#return results
a4=list("Results of Educational Status MANOVA",
print(d),
summary(a3, test="Hotelling-Lawley"),
summary(a3, test="Roy") ,
summary(a3, test="Pillai"),
summary(a3, test="Wilks"),
summary.aov(a3)
)
print(a4)
}
This function works as is, but I want to add the mean and standard
deviation to my table. When I add the following code to line 36
where I print "d"
print(d, prmsd=TRUE)
The numbers in my table disappear. When I use the same commands from
the command line, the same thing happens. After reading the manual,
I think the error might be due to the missing numbers in my
database, so I tried adding na.action to my set of commands:
print(summary.formula(a2$Edu~a2$Kyph+a2$HL+a2$Vert, na.action,
method="reverse", overall=T, continuous=5, add=TRUE, test=T),
prmsd=TRUE)
but then I get the following error:
Error in as.data.frame.default(data, optional = TRUE) :
cannot coerce class '"function"' into a data.frame
It may be trying to do something with 'data' and doesn't find a 'data'
object until it get to the 'data' function.
Any ideas?
Also, does anyone know what kind of test statistic this function
calculates?
Huh. You do realize this function in the rms package has a help page,
right?
I compared the F and p values to a manual ANOVA but they were
different.
I think you break further questions down into components and post
something that is reproducible.
####------------------------------------------------------------####
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
####------------------------------------------------------------####
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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