Statistical - Cubic Regression (Cubic Spline Fit) ?

[Thomas Klemm]

Quote:achieve my goal with the least amount of key presses possible

You can do this by assigning the programs to dedicated keys on the HP-41C, or then creating a CUSTOM menu on the HP-42S.

Thank you for raising this question and for letting me learn something new today.
Now I might go a little deeper into the matter:

Quote:An alternative way to eliminate taking square roots in the \( \mathbf {LL} ^{\mathrm {*}} \) decomposition is to compute the Cholesky decomposition \( \mathbf {A} =\mathbf {LDL} ^{\mathrm {*}} \), then solving \( \mathbf {Ly} =\mathbf {b} \) for y, and finally solving \( \mathbf {DL} ^{\mathrm {*}}\mathbf {x} =\mathbf {y} \).