HP 80: What the heck is going on behind the curtain?

[Paul Dale]

(11-27-2019 10:35 PM)Dave Britten Wrote:  Press Shift-mean-x (the ->Sigma function) and now the sum of x is back in X, and n is back in Y. From here, you can continue using Sigma+/- to accumulate data. This reversal seems to happen instantly, unlike the forward calculation of mean and standard deviation, which makes it seem like it's pulling the numbers back out of temporary registers...

The reversal is multiplying the average by n and rearranging the stack. I doubt anything is stored in a temporary register.


Pauli