[HP-12C] Angular coefficent from linear regression off by 1

[Werner]

I don't know either the 12C or the 15C very well but I have emulators on my phone ;-)

So, correct me if I'm wrong, but the 12C doesn't have linear regression as a function, just x-intercept and y-intercept. So you calculate the slope in two steps:
y | x=1 minus y | x=0

or

1 g(y,r) (11.25867251)
0 g(y,r) (0.15934086.19)
X<>Y
RDN
-

If you do the same on a 15C, you get the same result. But a 15C has a f(L.R.)
function delivering the result without 10-digit intermediate calculations. Hence the difference.

Cheers, Werner