Try the standard deviation.... Want a refund! – RK-83: Scientific Graphing Calculator Review

Here's an if-then review: IF a calculator gives an output of "your mum", THEN it is dies not function as advertised. I would like a refund, and I urge the devs to either fix their program, or give me me my function money back. :( boo hiss.
Review by Mel T. Chiez on RK-83: Scientific Graphing Calculator.