Bounding QuestQuantile

1
We are having some difficulty with QuestQuantile returning values
<0 and >1. Since QuestQuantile is designed to return intensity we do
not understand why it is leaving the range of 0->1. Is there some
way to bound the range of questquantile so that it stays within a
fixed range?

Thanks, William Wigfield
Color and Vision Research Lab.
University of California, San Diego
2
> We are having some difficulty with QuestQuantile returning values
><0 and >1. Since QuestQuantile is designed to return intensity we do
>not understand why it is leaving the range of 0->1. Is there some
>way to bound the range of questquantile so that it stays within a
>fixed range?
>
>Thanks, William Wigfield
>Color and Vision Research Lab.
>University of California, San Diego


dear william

i think you're confusing "quantile" with probability. probability (e.g.
"quantileOrder") is restricted to the range 0 to 1. a quantile is an
INTENSITY that bounds an interval containing a specified probability.
intensity is unbounded. it can go from minus infinity to plus infinity.
Thus a median is a 0.5 quantile and is the intensity such that threshold
has a 0.5 chance of being below it.

you're asking Quest for a quantile and you're getting it, but apparently
you want something else. do you want the cumulative probability
associated with a particular intensity? (that's the inverse of what
QuestQuantile does.)

does that help?

best

denis