Here is a picture of my Abacus AU5007 Palm OS wristwatch running powerOne(R) Graph in "HP 48" mode showing a chi-square plot.
With all this talk about accepted and banned handheld calculators for exams: the Fossil/Abacus Palm OS watches will run Infinity Softwork's powerOne Graph and Finance software. My powerOne Graph is version 4.2.3 and Finance is version 5.1.4. I usually use powerOne Finance, because the digits in the display area are larger, and use Graph when I really have to.
As for text string capabilities, I am now pretty comfortable with Jot which lets you "handwrite" directly on the screen, though one character at a time.