Simple Error Bar

Hi,
               Basic question with basic code.   I am simulating a set of
'y' values for a standard 'x' value measurement. So here the error bars
are very long because the
number of samples are very small. Is that correct ? I am plotting the mean
of 'y' on the 'y' axis.


Thanks,
Mohan

x<- data.frame(c(5,10,15,20,25,30,35,40,50,60))
  colnames(x)<- c("x")

  y<- sample(5:60,10,replace=T)
  y1<- sample(5:60,10,replace=T)
  y2<- sample(5:60,10,replace=T)
  y3<- sample(5:60,10,replace=T)
  y4<- sample(5:60,10,replace=T)

  z<- data.frame(cbind(x,y,y1,y2,y3,y4))
  z$mean<- apply(z[,c(2,3,4,5,6)],2,mean)
  z$sd<- apply(z[,c(2,3,4,5,6)],2,sd)
  z$se<- z$sd / sqrt(5)