In reply to Rick Wicklin.

Thanks much Rick.

I am comparing several qq plots so , I used proc univariate for most, but for igauss I used the above step via calculating quantile. To make sure I am comparing the same qqplots, for iguass I calculated quantile as:
q=quantile("igauss",v,shape parm) ; where I calculated the shape parameter via proc univariate.

Is that correct? Or some other transformation is necessary?

Thanks.