[R] Summary.Formula: prmsd and test statistic
Eli Kamara
eli.kamara at gmail.com
Sat May 14 17:23:30 CEST 2011
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)
#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
Any ideas?
Also, does anyone know what kind of test statistic this function calculates? I compared the F and p values to a manual ANOVA but they were different.
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