[R] R-help Digest, Vol 109, Issue 9

[Terry Therneau]

On Fri, 2012-03-09 at 12:00 +0100, r-help-request at r-project.org wrote:
> > A note on standard errors: ?S(t) +- std is a terrible confidence
> > interval. ?You will be much more accurate if you use log
> scale. ?(Some
> > argue for logit or log-log, in truth they all work well.) ? If n is
> large
> > enough, however, you should be ok.
> 
> Very true, but if one really wants a confidence interval for
> S_1(t)-S_2(t)  (not for S_1(t)/S_2(t)) then one is pretty much forced
> to use the raw probability scale.
> 
>     -thomas

 I agree, and stand corrected.