I recently bought a Casio FX-991EX. I am in high school and orientate myself in physics. The statistics has a formula y=a+bx. I, for example, have an experiment where i get bunch of m (x) and l (y), i put those points in a graph and draw a line that suites all the points (linear regression) and calculate k from that line using kl=mg. I see that i could enter those values in the calculator and get b (y=a+bx where y is l, a is 0, x is m and b = g/k), but how can let the calculator know that a = 0 (or generally in every statistics formula that b or a is a number that i know) or something like that?