the standard deviation of 5, 5, 5, 2, 5, 3, 5 is not 924.4, and the mean is not 12

[solarbird]

I've been playing with this elderly Radio Shack scientific calculator I have, and when it took me five tries to get a correct set of standard deviation answers, I figured out that its code has undocumented gotchas like "clearing the calculator in standard deviation mode doesn't actually clear out everything, some of the registers still have crap in them and you have to clear it repeatedly in multiple modes or your answers will be strange after the first time you use it, and this persists even if you power it off in between runs, and by the way, we don't tell you this anywhere." Since WarGames taught us all that the only way to win that kind of game is not to play, I need a new calculator.

[Poll #754638]

Comments

[kirbyk.livejournal.com]

The nice thing about RPN is that it's totally deterministic without needing parenthesis. Once you get used to it, it's easy to do complicated calculations on an RPN calculator that would be tricky to do on a normal one.

On the other hand, modern calculators have parenthesis (My TI-80 that I got in the late eighties did).

But that's why they're cool. And the trick is just to think in stacks, which is easy with a computer science background.

[solarbird]

Other than RPN, is there anything you like significantly better about HP than TI calculators?

[wrog]

better workmanship. HP calculators last a lot longer.

[wrog]

of course this may have gone down the tubes now that Compaq owns them. They probably kept the DEC field service people, too.

[frobzwiththingz.livejournal.com]

my HP-10C started having keyboard problems a couple of years ago. Luckily, HP recently started making RPN calculators again; i got a
33S. Been happy with it so far.

Once you get used to doing things the RPN way you'll never want to
use an "algebraic notation" calculator with those stupid parentheses ever again. Stacks Rule.

[solarbird]

Okay, tho' on the TI, you get a happy command line that lets you enter the entire equation (including parentheses) and hit ENTER, so very much like typing in the equation you want to solve. Other than RPN, is there anything you like significantly better about HP than TI calculators?

[spazzkat.livejournal.com]

geek

[solarbird]

Um, yeah, I think I've found another place you can stick those pocky.

[kathrynt.livejournal.com]

RPN is SO. MUCH. EASIER for multistage calculations that I can't even tell you. Parens in regular notation are a hack to accomplish the same thing, but they require you to construct the calculation from the end backwards, rather than forwards.

[kathrynt.livejournal.com]

otoh the TI calculators are much more _standard_ these days, and if any calculatory assistance is given, it'll be for the TI.

[solarbird]

Other than RPN, is there anything you like significantly better about HP than TI calculators?

[lisa-marli.livejournal.com]

My son loves his TI 84 Plus Silver Edition. It is not only a great calculator, but it has games! A lot of the kids at his high school are using it.

And it holds up to teen agers, which means it can handle anything and any one.

Good Luck in the Great Search!

[cafiorello.livejournal.com]

Derek has had a TI-84 for many years, I have yet to find *anything* he can't do with it. He programmed his own homework notebook, draws, programs games, builds shortcuts in for all of his math tests....

I, on the other hand, am never far from a computer with SPSS-14 on it.

Cathy

[gerimaple.livejournal.com]

i bought a no-name from the SFU bookstore for under $10CAN. so far, so good. and since it was the first week of classes at the time, i got to the register and it was 10% off!

good luck on finding the right one for you

[mathmuffin.livejournal.com]

I discovered that the more mathematics I learned, the simpler the calculator I purchased. All the equations I want are in my head, and I like to tweak them on the fly to suit my current purpose. So today I use a $4 Sharp scientific calculator, chosen because it lacked the annoying features of my previous calculator, such as a five-minute power-off and Sharp's half-backwards Advanced D.A.L. If I want to do serious repetitive calculations, I use a computer.

My daughters had to use TI-84 graphing calculators in high school. They liked them.

To add to the discussion on RPN, the "Polish" in the name is because we Americans have trouble pronouncing the name of Polish mathematician Jan Łukasiewicz. It is really Reverse Łukasiewicz Notation.

Erin Schram

[solarbird]

I've never used that much of the capability of any calculator I've had either, mostly because I haven't had any good ones ^_^, plus in general they've been actively discouraged. But in this class, strangely, they've been strongly encouraged. Particularly ones that can solve linear systems and do your std. deviation and stat work for you. It's odd.

In my case, I have issues with the doing it in my head part, I tend to swap digits and stuff, so it's actually likely to be helpful to have a calculator now that it's not just permissible but in fact strongly recommended.

[rmd.livejournal.com]

so, yeah, i had an hp15 that died on me in the middle of a stats exam (at which point i wrote in the exam book, "my calculator has just died. i'll be showing a lot of work but may not get all the calculating done"), so then i got an hp42 or somethign like that.

i don't know what the TI and similar calculators can do because i've been using HPs since i was in high school, but things i liked about it when i was in college were the ability to solve matrices, the ability to have some stored constants available easily within a few clicks, a couple of useful programs stored, and of course the rpn-ness.

[janne.livejournal.com]

Hmm. I just realized that the calculator I've been using for the last... 22 years or so is a Casio. (The fx-180P Scientific Calculator, in fact). Extremely robust and versatile -- if only I hadn't misplaced the user manual a decade ago :P All these lovely programmable functions and I can't recall how to use them. Do they even sell Casio's anymore?

[solarbird]

Sure! I saw a couple at the bookstore in bubble-wrap on the wall. But they aren't as capable as the TIs and HPs.

RPN vs. Arithmetical

[stickmaker.livejournal.com]

Try using a gadget which mixes 'em.

Seriously. The issue adding machines at work use RPN for adding and subtracting, and arithmetical for multiplication and division.

This almost makes sense. Adding machines are primarily used for adding and subtracting long chains of numbers (using the tape to proof). Then the total is sometimes multiplied or divided. It's still awkward.

Which makes it typical for the Kentucky state government office environment.

[epawtows.livejournal.com]

I still use my college-era HP 15-C; other than RPN (which is very popular among MechE's) thing things I like about it: size/layout is good for lots of rapid calculations (cradle in two hands and rapidly press buttons with thumbs, although it's been over a decade since I had that many calculations to do at once), the 'feel' of the buttons is excellent, and the thing is so tough I'm not sure if running it over with a car would hurt it. For it's day it had a very readable display.

I don't know how much this applies to modern HP's, though.

[solarbird]

If you have the classical wider-than-tall rectangular shape, those are mostly gone. All the ones I'm looking at are shaped more like remote controls, only big enough to kill small animals. Assuming I get one of the ones I'm looking at now, I'm going to rename it the Sealclubber 6000.

[tinlail.livejournal.com]

If you are not already part of the RPN cult I wouldn't join now.
Calculators have a ton of power, and don't get as much benefit from having data input in RPN. I think in this day and age you ought to think about using a laptop for data analysis, and have your calculator only to handle the restriction imposed for tests.