SUM, MEAN & SDEV don't lift the stack

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Walter
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Re: SUM, MEAN & SDEV don't lift the stack

Post by Walter » Fri Sep 28, 2018 4:13 am

Thomas Okken wrote:
Fri Sep 28, 2018 2:01 am
I only know how SUM, MEAN, and SDEV work on the 25/25C, 19C/29C, 67/97, 41C/41CV/41CX, and 42S, and among those calculators, the 25/25C only compute the mean and standard deviation of x, lifting the stack like you would expect, while all the others compute the mean and standard deviation of x and y, doing that weird thing of not lifting the stack, dropping y, and saving x in LASTx.
Nope. The 29C/19C work like the 25/25C in this matter. Neither one could do a linear regression straight ahead due to lack of one required sum IIRC.

Will check Spices and other Pioneers later today.
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Re: SUM, MEAN & SDEV don't lift the stack

Post by Thomas Okken » Fri Sep 28, 2018 4:44 am

Walter wrote:
Fri Sep 28, 2018 4:13 am
Nope. The 29C/19C work like the 25/25C in this matter. Neither one could do a linear regression straight ahead due to lack of one required sum IIRC.
A bit more emphasis on the "IIRC" part would be appropriate here. You do not remember correctly. Do you ever do any research before sounding off? :shock:

I used to own a 19C, back when it was new. It does collect all the sums, including y^2, and it does compute mean and standard deviation in x and y. It's all in the manual, right there in the MoHPC documentation set. A great reference, in case your memory isn't perfect.

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Re: SUM, MEAN & SDEV don't lift the stack

Post by dlachieze » Fri Sep 28, 2018 5:15 am

On the 32s and the 32sii you recall separately the mean of x and the mean of y, not both at the same time. If you recall the mean just after the last Sigma+, it replaces the content of X (stack lift is disabled after Sigma+), if there is another operation enabling stack lift after the last Sigma+ then the mean goes to X, lifting the stack. Same for the sums and standard deviations.
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Walter
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Re: SUM, MEAN & SDEV don't lift the stack

Post by Walter » Fri Sep 28, 2018 5:15 am

The Spices do it like the Voyagers (tested on a HP-32E).

And the HP-32S as well as the HP-32SII don't have the problem, since their menu system doesn't allow for recalling two statistical results together (tested on a HP-32S and a HP-32SII).

So the only exception from a sensitive stack handling seems to be the HP-29C/19C as reported by Thomas. And the HP-67, 41C, and 42S, which may go back to the HP-65 in this matter. Have to check.
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Re: SUM, MEAN & SDEV don't lift the stack

Post by dlachieze » Fri Sep 28, 2018 8:23 am

Walter wrote:
Fri Sep 28, 2018 5:15 am
So the only exception from a sensitive stack handling seems to be the HP-29C/19C as reported by Thomas. And the HP-67, 41C, and 42S, which may go back to the HP-65 in this matter. Have to check.
The first HP calculator with 2 variables stat functions is the HP-55. On the HP-55 MEAN and SDEV are overwriting X and Y, no stack lift. This is clearly documented in the manual.
This is also how it works in the following 67, 27, 29C/19C, 41C and 42S. So this is the original stack handling being in use from 1975 to 1988.

It appears this has been changed for the Spice and the Voyager follow-ups.

For backward compatibility the 41C needed to work the same way as the 67. Same for the 42S.
Now, why has it been changed in the Spice, we may never know…
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Re: SUM, MEAN & SDEV don't lift the stack

Post by Walter » Fri Sep 28, 2018 1:05 pm

dlachieze wrote:
Fri Sep 28, 2018 8:23 am
The first HP calculator with 2 variables stat functions is the HP-55. On the HP-55 MEAN and SDEV are overwriting X and Y, no stack lift. This is clearly documented in the manual.
This is also how it works in the following 67, 27, 29C/19C, 41C and 42S. So this is the original stack handling being in use from 1975 to 1988.<br/>

It appears this has been changed for the Spice and the Voyager follow-ups.

For backward compatibility the 41C needed to work the same way as the 67. Same for the 42S.
The first HP pocket calc "with statistics" was the HP-45, summing and evaluating one variable only. It was followed by the HP-25/25C. Thereafter, all pocket calcs sported 2D statistics.

The first HP featuring 2D statistics and L.R. as a built in function was the HP-55. It was followed by the HP-22, 27, 29C/19C, and 67/97 (though the latter two pairs don't feature L.R.). All these overwrite x and y when statistical functions returning 2 values are called.

Thereafter, the HP-32E, 33E/C, 34C, 10C, 11C, 12C, and 15C all featured 2D statistic and built-in L.R. When statistical functions returning 2 values are called, all these models push the output on the stack. I can't tell about the way the HP-37E and 38E/C handle the stack but assume it's the same.

The HP-41C and HP-42S returned to the old paradigm overwriting two stack levels.

And further RPN calcs didn't return two statistical values anymore.

Personally, I think the Spice and Voyager way of dealing with double returns is more logical for an RPN calc. Hence, we implemented it in the WP-34S and 31S. And we are going to implement it in the 43S as well.
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Re: SUM, MEAN & SDEV don't lift the stack

Post by Thomas Okken » Sat Sep 29, 2018 1:45 am

Walter wrote:
Fri Sep 28, 2018 1:05 pm
The first HP pocket calc "with statistics" was the HP-45, summing and evaluating one variable only. It was followed by the HP-25/25C. Thereafter, all pocket calcs sported 2D statistics.

The first HP featuring 2D statistics and L.R. as a built in function was the HP-55. It was followed by the HP-22, 27, 29C/19C, and 67/97
The HP-55 was introduced after the 25?

The MoHPC just states both were introduced in 1975, but I always assumed that all the Woodstocks were introduced after the Classics. Learn something new every day!

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Re: SUM, MEAN & SDEV don't lift the stack

Post by Walter » Sat Sep 29, 2018 2:49 am

Thomas Okken wrote:
Sat Sep 29, 2018 1:45 am
Walter wrote:
Fri Sep 28, 2018 1:05 pm
The first HP pocket calc "with statistics" was the HP-45, summing and evaluating one variable only. It was followed by the HP-25/25C. Thereafter, all pocket calcs sported 2D statistics.

The first HP featuring 2D statistics and L.R. as a built in function was the HP-55. It was followed by the HP-22, 27, 29C/19C, and 67/97
The HP-55 was introduced after the 25?

The MoHPC just states both were introduced in 1975, but I always assumed that all the Woodstocks were introduced after the Classics. Learn something new every day!
Come on Thomas, if you want to misunderstand then feel free to do so. I wrote of two "statistics lines", one starting with the 45, the other with the 55 - I didn't state anything about their start times. But if you want... :roll:
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Re: SUM, MEAN & SDEV don't lift the stack

Post by Thomas Okken » Sat Sep 29, 2018 5:11 am

Walter wrote:
Sat Sep 29, 2018 2:49 am
Thomas Okken wrote:
Sat Sep 29, 2018 1:45 am
Walter wrote:
Fri Sep 28, 2018 1:05 pm
The first HP pocket calc "with statistics" was the HP-45, summing and evaluating one variable only. It was followed by the HP-25/25C. Thereafter, all pocket calcs sported 2D statistics.

The first HP featuring 2D statistics and L.R. as a built in function was the HP-55. It was followed by the HP-22, 27, 29C/19C, and 67/97
The HP-55 was introduced after the 25?

The MoHPC just states both were introduced in 1975, but I always assumed that all the Woodstocks were introduced after the Classics. Learn something new every day!
Come on Thomas, if you want to misunderstand then feel free to do so. I wrote of two "statistics lines", one starting with the 45, the other with the 55 - I didn't state anything about their start times. But if you want... :roll:
Come on Walter. I know that it is somehow very difficult for you to acknowledge your mistakes, but this is really ridiculous.
The first HP pocket calc "with statistics" was the HP-45, summing and evaluating one variable only. It was followed by the HP-25/25C. Thereafter, all pocket calcs sported 2D statistics.
Please explain to me how this does not mean that the 45 was first, 25/25C second, and everything else came after. Are you making up your own version of English as you go along?

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Re: SUM, MEAN & SDEV don't lift the stack

Post by Walter » Sat Sep 29, 2018 6:12 am

I give up. No way for a foreigner to convince an unwilling semi-native writer in writing.

Anyway, I won't step back from my statement above that pushing two calculation results on the stack is more logical than overwriting two stack levels in my view. Thus, the 43S will act this way (as all the Spices, Voyagers, WP34S, and WP 31S did before).
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