NORMALD_ICDF (LEFT/CENTER/RIGHT)

[parisse]

I (and probably HP too) do not want to add new keywords for something that seems very specialized. If you can find existing keywords that fit better than center or tail, I can change to these keywords. I don't think it's really important, because either HP adds an UI, then the user will not have to worry about, or they don't support this enhancement and only a few experts will know about that...