[R] plotting lm coeficients with their means

[Andy Bunn]

How about something like this?

my.func <- function(y, x1, x2, x3, x4  = NULL){
    my.formula <- as.formula("y ~ x1 + x2 + x3 + x4")
    if(is.null(x4)) { my.formula <- as.formula("y ~ x1 + x2 + x3") }
    outlm <- lm(my.formula)
    meanvec<-c(mean(x1),mean(x2),mean(x3))
    if(is.null(x4) == F) { meanvec<-c(mean(x1),mean(x2),mean(x3),mean(x4)) }
    mf <- data.frame(Impact = outlm$coef[-1], Performance = meanvec)
    plot((mf),xlab="Impact",ylab="Performance", type = "n")
    points(mf, pch=21, bg="grey", cex=4)
    text(x = mf$Impact, y = mf$Performance, labels = rownames(mf))
    abline(h=mean(mf$Performance))
    abline(v=mean(mf$Impact))
}

response <- 1:10
pred.1 <- rnorm(10)
pred.2 <- runif(10)
pred.3 <- pred.1 + runif(10)
pred.4 <- runif(10)
my.func(y = response, x1 = pred.1, x2 = pred.2, x3 = pred.3)
my.func(y = response, x1 = pred.1, x2 = pred.2, x3 = pred.3, x4 = pred.4)


You'd have to do some work to generalize it further. I don't have much
experience writing functions with missing args and I expect this is a dumb
way of doing it.

HTH, Andy




> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Derek Margetts
> Sent: Monday, November 08, 2004 11:39 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] plotting lm coeficients with their means
>
>
> I am trying to write a function that will run a linear
> model and plot the regression coeficients with their
> corresponding means.  I am having two problems.  I can
> get the plot with the function below, but I am having
> trouble labeling the points.
>
>
> function(y,x1,x2,x3,x4){
> outlm<-lm(y~x1+x2+x3+x4)
> imp<-as.data.frame(outlm$coef[-1])
> meanvec<-c(mean(x1),mean(x2),mean(x3),mean(x4))
> out<-list(imp,meanvec)
> mf<-as.data.frame(out)
> plot((mf),xlab="Impact",ylab="performance")
> abline(h=mean(meanvec))
> abline(v=mean(imp))
> }
>
> Problem #2:  If I only input x1,x2,and x3 how do I get
> the function to ingnore the 4th instead of giving me
> the unused argument error?
>
> Thanks
> Derek
>
>
>
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