[R] Problems with "predict" function ii

[WRAY NICHOLAS]

I  have realised that I should have used "detach" before attaching another
dataframe, but even when I do this it's still giving me lots of lines, rather
than just one:

My code:


m<-runif(1,0,1)
m
mres<-m*(seq(1,12))
mres
ssd<-rexp(1,1)
ssd
devs<-rep(0,length(mres))
for(i in 1:length(mres)){devs[i]<-rnorm(1,0,ssd)}
devs
plot(-10,-10,xlim=c(1,24),ylim=c(0,20000))
sales<-round((mres+devs)*1000)

points(sales,pch=19)

ptr<-cbind(1:length(sales),sales,sales,sales)

ptr
sdf<-data.frame(cbind(1:nrow(ptr),sales))
sdf

colnames(sdf)<-c(“monat”,“mitte”)
sdf
attach(sdf)
s.lm<-lm(mitte~monat)

s.lm
abline(s.lm,lty=2)
news<-data.frame(monat=nrow(sdf)+1)
news
fcs<-predict(s.lm,news,interval=“predict”)
fcs

points(1+nrow(ptr),fcs[,1],col=“grey”,pch=19)
points(1+nrow(ptr),fcs[,2])
points(1+nrow(ptr),fcs[,3])
ptr<-rbind(ptr,c(1+nrow(ptr),fcs[2],fcs[1],fcs[3]))
ptr

highdf<-data.frame(ptr[,c(1,4)])
highdf
colnames(highdf)<-c(“month”,“sales”)
highdf
detach(sdf)
attach(highdf)
h.lm<-lm(highdf[,2]~highdf[,1])
h.lm
abline(h.lm,col="gray",lty=2)
news<-data.frame(month=nrow(ptr)+1)
news
hcs<-predict(h.lm,news,interval=“predict”)
hcs
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