Stat summation registers Message #5 Posted by Karl Schneider on 6 Dec 2009, 3:19 p.m., in response to message #4 by Norman Dziedzic
Norman --
It seems that you've got it figured out, but here's some background for everyone:
For those HP's that do statistics using the summation method (instead of maintaining all input data, such as the RPL-based models, HP-17B/BII, HP-27S, and HP-71B), a set of six numbered storage registers was utilized for summation.
Most legacy models use a fixed set of registers. The HP-11C and HP-34C used R0-R5, as those would be the last to be deallocated for programming storage. The HP-15C uses R2-R7, because R0 and R1 must be preserved for matrix indices.
The HP-41 utilizes a set of six consecutive registers, user-selectable by the (Sigma)REG function. The HP-41CX added (Sigma)REG? -- which is not available in the X-Functions module -- to allow the user to identify the first summation register. The user is responsible for allocating a sufficient number of registers for numerical storage (SIZE), and that the selected value of (Sigma)REG allows for six summation registers.
The HP-42S, for compatibility with the HP-41, did the same. Both (Sigma)REG and (Sigma)REG? are standard in the HP-42S.
The HP-32S and its descendants do this better than all the others:
They use the pool of unallocated RAM for the statistical registers. Each summation value can be recalled individually, but values are set and updated only via CLEAR(Sigma), (Sigma)+, and (Sigma)-.
-- KS
Edited: 6 Dec 2009, 5:31 p.m. after one or more responses were posted
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