Where is linear regression on an HP41  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: Where is linear regression on an HP41 (/thread229077.html) 
Where is linear regression on an HP41  Palmer O. Hanson, Jr.  08122012 I wanted to do a linear regression on my HP41CV. I did a Clear Sum and entered the data pairs using Sum+ . But I can't find the instruction to do a linear regression. I have looked in the manual and have SST'd through the catalog. So, what is the instruction for linear regression?
Re: Where is linear regression on an HP41  Dieter  08122012 Palmer, there are no regression commands on the HP41. That's why the the standard applications booklet that came with the '41 included such a program. For linear as well as nonlinear regression. You will also find it here on hpmuseum.org in the HP41 software section. You just have to key it into your '41. Or get the standard pac, a ROM module that included all the programs in that booklet.
Dieter
Re: Where is linear regression on an HP41  Gerson W. Barbosa  08122012 Quote: The Advantage Pac is a better option. I don't know which one is more easily available though.
Gerson.
Re: Where is linear regression on an HP41  Patrice  08122012 Hi Palmer, On a vanilla 41C, you only have the stat registers which gives you everything needed for a linear regression. You have to apply the formulas by yourself, it is usually done with a little program. It was the good time of self made tools :)
Patrice
Re: Where is linear regression on an HP41  Namir  08122012 Did HP run out of ROM space to implement the linear regression calculations? The TI59 (the rival of the 41C) had a special OP command that performed linear regression.
Namir
Re: Where is linear regression on an HP41  Dieter  08122012 Yes, the TI58/59 used OP 12 ... OP 15 for linear regression, while the 41C did not provide such functions. On the other hand, do you think TI ran out of ROM space so that they did not include a factorial function, or something like e^x1 and ln1+x, H.MS arithmetics, a remainder function, decimaloctal conversions etc. etc. ?) All this is included in a standard 41C. Calculating the two parameters of a linear regression is simple and straightforward. Providing an exact ln1+x function is not. So I'm glad HP used the available memory for the trickier cases. ;)
Dieter
Re: Where is linear regression on an HP41  Ángel Martin  08122012 The SandMath has MCODE functions for LR, Y, COV and CORR, all courtesy of JeanMarc Baillard
forgot to mention: in this implementation I used 13digit OS routines, no like the user code programs. Edited: 12 Aug 2012, 6:29 p.m.
Re: Where is linear regression on an HP41  Mike Morrow  08122012 Quote: I doubt that many who were contemporary with the introduction of these machines considered the 1977 TI59 to be a rival of the 1979 HP41C. Most considered it to be the rival of the 1976 HP67. If anything, the HP41C was introduced as a rival to the TI59.
IMHO, the HP41C series was a nextgeneration trek into new territory and never had a comparable subsequent TI rival, in the sense of something that was created as a response to it and as widely distributed. Edited: 12 Aug 2012, 7:26 p.m.
Re: Where is linear regression on an HP41  Luiz C. Vieira (Brazil)  08122012 Hi. Allow me to add that I cannot see neither consider a reference to compare both. Apart of the fact they are both programmable scientific calculators, what I can think as differences in order to compare both are:
 arithmetic notation  AOS x RPN Cannot think of any other major differences, considering the ones I pointed out are actually major. So, there are many different points setting them apart of each other, comparing both should not lead to fair conclusions. Cheers.
Luzi (Brazil) Edited: 12 Aug 2012, 8:35 p.m.
Re: Where is linear regression on an HP41  Gerson W. Barbosa  08122012 Hello Ángel,
Quote: That's why I said 'a better option', not 'the best option' :) All the best,
Gerson.
Re: Where is linear regression on an HP41  Namir  08122012 Mike, I stand corrected. You are right! The TI59 was the rival of the HP67/97.
Namir
Re: Where is linear regression on an HP41  Gerson W. Barbosa  08122012 Quote:
Might the never released TI88 have been a valid competitor?
Re: Where is linear regression on an HP41  Mike Morrow  08122012 Quote: That's exactly what I thought back then, and today still. That's why I had to qualify my characterization of no TI rival to the HP41C with "in the sense of something that was created as a response to it and as widely distributed." The TI88 didn't meet those last three words. :)
It's too bad...I was looking forward to the TI88. But back then, I was even interested in the TI99/4 and 99/4A.
Re: Where is linear regression on an HP41  Palmer O. Hanson, Jr.  08122012 Quote:I was heavily involved in the socalled "friendly competition" back in those days. The way I remember it is The HP67 and the TI SR52 were roughly comparable in calculating capability. The major advantage of the SR52 was the ability to connect to the PC100 printer. The TI59 clearly outclassed the HP67 with three major advantages: more user memory, the solid state modules and the ability to connect to the PC100 printer. The HP41 clearly outclassed the TI59 with major advantages such as LCD rather than LED display, speed, and more user memory, particularly with the use of memory modules with the HP41C and more internal memory with the HP41CV and HP41CX. The TI88 was expected to be a competitor to the HP41 series but never made it to market. There were some problems with the hardware, and in particular with the keyboard which was of the same family as the TI55II. At the same time TI abandoned the TI59 in favor of emphasis on trying to dominate the early PC market with the TI99/4. Eventually, TI tried to reenter the high end scientific calculator market with the TI95. It's major disadvantage was it's size. Two major advantages relative to the HP41 were speed and the programmable memory modules. After only a few years the TI95 was abandoned when TI decided to enter the education market with the TI81. It would be difficlt to fault them for that decision from a corporate standpoint.
Back to the availability of linear regression. I don't have most of my collection here but I thought that I remembered that some of the earlier machines did offer linear regression as a keyboard option. I reviewed the descriptions for a few of the machines using the descriptions in this Museum and found that the HP22, HP27, HP32E and HP33E did have linear regression as a keyboard options and the HP25, HP29 and HP67 did not. My personal preference is for a keyboard capability.
Re: Where is linear regression on an HP41  Namir  08132012 The TI95 is a very capable AOS machine. It takes one plugin module and has a printer port. It can be seen as somewhat a competitor of the 41C, but not a serious rival.
Namir
Re: Where is linear regression on an HP41  Gerson W. Barbosa  08132012 I had a TI59 for a while in '82, until it was stolen. I would surely have chosen the TI88 as a replacement if it were available, since I was used to TI (previously I had a TI51III). I ended up getting an HP15C instead because of its looks and because it was less expensive. At first I was disappointed because there were no equals keys. Only at first, though :)
Re: Where is linear regression on an HP41  Namir  08132012 Of course the STAT 1 module made up for the lack of builtin linear regression by providing for linear regression for 2, 3, and 4 variables as well as quadratic and cubic polynomial regression.
Namir
Re: Where is linear regression on an HP41  Mike Morrow  08132012 Quote: I always considered at the time the 1975 SR52 to be the rival of the 1974 HP65. Other than the PC100 capability of the SR52, it had nothing to recommend it over the 1976 HP67...and never would I consider it otherwise comparable to the HP67.
Quote: The 1977 TI59 was very impressive technically, compared to the HP67. But its reliability was terrible...I've recounted here many times before that I used up five TI59s and three PC100s between 1977 and 1981, during which time I only had to send in my HP67 once, in 1980. When I had to have some hardware that I knew would work such as for submarine propulsion and navigation applications, I had to have the HP67 or 97.
The industrial design and color scheme of the SR50A through the TI59 was also terrible aesthetically. I wonder if that is what "inspired" HP to adopt similarly ugly poorcontrast color schemes for the HP48, 38G, and Pioneer series.
Re: Where is linear regression on an HP41  Palmer O. Hanson, Jr.  08132012 Quote:My records show that I have the following modules: MathPac with manual 14001 MathPac with manual 15002 StatPac with manual Financial Decisions Pac with manual Thermal Pac without manual Unfortunately I only have the MathPac with me and I didn't bring the manual.
Palmer
Re: Where is linear regression on an HP41  Gerson W. Barbosa  08132012 Quote:
The manual is available as TOS. Table of Contents:
Gerson.
Re: Where is linear regression on an HP41  Palmer O. Hanson, Jr.  08132012 Quote:Curiously enough, when the HP67 was released the editor of 52 Notes wrote much the same sort of thing about the HP67  disappointing, and no reason to buy it. Quote:I have never understood all the horror stories about the TI59. I worked at Honeywell. The company participated in TI's Productivity program where any employee could get a TI59 of his own by taking a short introductory course. So there were literally a thousand or so TI59's around. The one problem which could give users the fits was the rarely occurring memory problem. I wrote a more thorough version of the memory test in the Service manual to check for that. I had one friend who refused to take the course and get his TI59. He insisted that his ditsy little HP25 was better because it used RPN. We all thought that was more than a little odd. During the period from the release of the TI59 to the release of the HP41 I knew of no one who thought that the HP67 was a serious competitor for the TI59. The editor of 52 Notes had a comment on that. He said that the HP users looked at their machines and thought "It just has to be better since I paid so much more."
The HP41 was clearly better than the TI59 in many ways. But I didn't like RPN and I worried about the accuracy of ten digit calculations instead of 13. Furthermore, I had purchased a Radio Shack Model 100 which could support some serious plotting capability and had switched to it for most of my work in inertial navigation until I retired. I didn't get an HP41 until I started collecting. Now I have four HP41's: a C, a CV, a CX and a C with the gold balls and two of the calculating errors. I also have both a HP82240A and HP82240B printer. I have to admit that all that hardware doesn't get very much use.
Re: Where is linear regression on an HP41  Mike Morrow  08142012 I wrote: "Other than the PC100 capability of the SR52, it had nothing to recommend it over the 1976 HP67...and never would I consider it otherwise comparable to the HP67."
Quote: That editor's statement was obviously unburdened by the weight of facts. It would be true in a comparison of the HP67 to the TI59...but not to the grossly less capable SR52. I had my ship purchase a SR52/PC100A for use in the nucleonics lab in early 1976, before either the HP67 or TI59 was available. When the HP67 appeared later, I found it to be a great advance over the SR52 in every way except printer capability and (as you mention) the greater accuracy of the SR52. At the cost of more than six weeks of my lieutenant(jg) pay I bought a personal HP67, my first HP, with a few accessories. The SR52 was clearly out of the contest, even though my personal calculators before then were all TIs purchased from 1974 to 1976...the SR50, SR51A, and SR56. The TI59 in 1977 was a stunning product at a very competitive price (except for its ugly industrial design and color scheme). If it had been available before I purchased the HP67, I doubt that I would have purchased an HP67 until experiencing all those many failures of TI quality. I bought my personal TI59/PC100A in 1977, and I liked it greatly because of its capabilities. The TI59 $300 price in 1977 was equivalent to almost $1200 today, compared to the HP67's $450 price, equivalent today to $1700.
Quote: The only thing to understand is that quality of manufacture was very obviously lacking...failures occurred under very benign and nonchallenging environmental conditions. My first TI59 died within a year. The replacement died within six months, as did the subsequent replacement and my first PC100A. When in 1981 my fourth TI59 and second PC100A died, I wrote the Chairman of TI, Mark Shepherd, describing my personal history with this product. I'm sure he never saw the letter, but I received a letter from an underling stating that a newlymade TI59 and PC100 would be tested and burnedin and then sent to me without cost (I had to pay for some of the earlier replacements), along with the address of a TI engineer who would be examining my failed units. The printer replacement was the lesscapable PC100C. I required hardware to serve reliably for fairly significant submarine reactor, nucleonics, equipment performance monitoring, and navigation applications. The TI59 failed repeatedly...the HP67 did not. That was a real shame, because the TI59/PC100A capabilities were better suited to my needs than those of the HP67, even after taking into account the inefficiency of the TI AOS which resulted in programs typically at least 40 percent longer than when implemented on the HP67.
Quote: I read of those programs with envy back then. TI had no such offerings for US Navy people. :)
Quote: Indeed. The HP25 was useful only for a very very limited set of applications, compared to those possible on the TI59. And TI never was so incompetent as HP to design a battery charging system that was guaranteed to destroy the calculator under conditions that were bound to occur naturally and inevitably...a shameful failure of HP to meet a trivial engineering problem from the heresorevered mythological Bill Hewlett era!
Quote: Experience...the best teacher...taught me how wrong sophomoric conclusions as these from that editor can be. In fairness, it is not likely that many TI59 users had applications that required use in realtime to reliably produce results that then were utilized immediately in a major process, as my applications (like a reactor high power calorimetric, or a seatraffic contact motion analysis) often required. I spent a lot more "hobby time" with my TI than with my HP. It was a much more interesting system when it worked. I really liked the TI59, but I never lost sight of its oft demonstrated lack of reliability. I stopped writing programs for the TI that were required for professional purposes.
Quote: I'd say that the HP41C series was better than the TI59 in every way except the accuracy issue. That issue remained with all HP machines until the appearance of the Saturnbased models...so HP recognized it eventually.
Quote: The Model 100...that's a real milestone from 1983 regardless of its slow speed and the oldeventhen 80C85 uP. I've got a couple of them that I used professionally in commercial nuclear plant engineering applications between 1984 and 1987. I loved its doubleprecision Basic in which some surprisingly sophisticated applications could be implemented.
Edited: 14 Aug 2012, 1:42 p.m.
Re: Where is linear regression on an HP41  Garth Wilson  08142012 I wonder if TI improved the quality a lot after the initial years. I got a TI58c in Dec '81 and later a 59 and used them both heavily, also the 100c printer, and never had any trouble with them except that after many years the 59's rubber wheel in the card drive deteriorated as they all do. In 20032005 our son used my 59 in high school. (I had sold the 58c before that.)
As for appearance, I initially thought the HP41 was kind of funnylooking (with its flat end where the modules plug in) compared to the TI59. I guess beauty is partly in the eye of the beholder though. To me, styling peaked about 1980 or soon after, and has been going downhill ever since, whether it's calculators, cars, appliances, stereos, whatever. It's ok that a friend thinks his wife is beautiful too. I won't tell him how wrong he is. LOL
