Hello, I would like to use qqplot() to compare two experimental distributions. But I do not understand how qqplot() compute quantiles. In fact, quantile() do not return the same results. Thank you for your help. Vincent.
On 2/6/2006 9:59 AM, Vincent Negre wrote:> Hello, > I would like to use qqplot() to compare two > experimental distributions. But I do not understand > how qqplot() compute quantiles. In fact, quantile() do > not return the same results.Take a look at the source code. qqplot replaces the longer vector with one calculated by linear interpolation (that's what approx does) between the values of the other. Duncan Murdoch
[Vincent Negre]>[...] I do not understand how qqplot() compute quantiles.Just type ``qqplot`` (without the parentheses) at the R prompt, to see the source code. ``qqplot`` does not especially compute quantiles, which are rather obtained directly through sorting its arguments. -- Fran??ois Pinard http://pinard.progiciels-bpi.ca