[R] QQ plot

Rolf Turner rolf.turner at xtra.co.nz
Sat Feb 18 00:13:13 CET 2012

On 18/02/12 00:15, nandan amar wrote:
> Thanks a lot Turner.
> Latter I also tried following :
> oo<-quantile(original, probs = seq(0, 1, 0.01), type = 8)
> pp<-quantile(predicted, probs = seq(0, 1, 0.01), type = 8)
> plot(oo,pp)
> But plot for above and following (as you suggested) are not same.
> What may be the error ?

The error is that you didn't look at the code of qqplot() to see what
it's actually doing.  (Type:    "qqplot" without the quote marks.)

It's not doing what you did, so naturally the results are different.

I have not the time nor the inclination to think through the implications
of what you did and what qqplot() does in respect of the information
content of the two approaches.  I suspect that they will usually, if not
always, give *similar* results.


         Rolf Turner

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