Retro Review: BA-55
02-20-2018, 09:54 PM (This post was last modified: 02-20-2018 10:03 PM by martinot.)
Post: #7
 martinot Junior Member Posts: 40 Joined: Aug 2017
RE: Retro Review: BA-55
(02-20-2018 01:41 PM)Eddie W. Shore Wrote:  The BA-55 has the [x<>y] key to:

1. Allow for bi-variate data entry: (x data [x<>y] y data [Σ+])

2. In two variable statistical analysis, pressing [x<>y] switches between standard deviation of x and standard deviation of y [σn-1]. This also applies for population deviation [ σn ].

3. The key also switch operands. This could be useful in correcting the order of the arguments in subtraction and division operations. Example: I want to calculate 78 - 26 but enter 26 - 78 by mistake:

26 [ - ] 78 (display: 78)
[x<>y] (switches the operands, display: 26)
[ = ] (result: 52, 78 - 26)

Ahh. That explains it. Thanks!

Looked very RPN-like at first.

(02-20-2018 01:41 PM)Eddie W. Shore Wrote:  Regarding the preference of y^x instead of x^y, I honestly have no idea.

Private guess and speculation; I wonder if they looked at HP calculators, and their buttons (it makes sense as a post-pix calculator, but not as in-fix), but not thinking too much about it?

I note that on newer TI calculator it is correctly (to be algebraic calculator) renamed to [x^y].

Trivia question: I wonder when (year? calculator model) TI changed their mind and went from printing [y^x] to [x^y] on the power key?

(02-19-2018 09:39 PM)Gene Wrote:  One other thing. The BA-55 can use the PC-200 printer originally aimed at the TI-66.

If you have a BA-55 where the keys work (as Eddie seems to have) you are very lucky!

Interesting! Never seen one IRL.

The P200 printer, is that TI's answer to HP's 82240A/B (or perhaps vice versa if TI was first)?

Is the printing technology about the same?

Does it connect over IR, or some serial interface?

HP 35s, HP 50g, HP Elite X3, SwissMicros DM42
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 Messages In This Thread Retro Review: BA-55 - Eddie W. Shore - 02-19-2018, 08:57 PM RE: Retro Review: BA-55 - Gene - 02-19-2018, 09:34 PM RE: Retro Review: BA-55 - Gene - 02-19-2018, 09:39 PM RE: Retro Review: BA-55 - Eddie W. Shore - 02-20-2018, 01:42 PM RE: Retro Review: BA-55 - martinot - 02-19-2018, 10:01 PM RE: Retro Review: BA-55 - Eddie W. Shore - 02-20-2018, 01:41 PM RE: Retro Review: BA-55 - martinot - 02-20-2018 09:54 PM RE: Retro Review: BA-55 - Massimo Gnerucci - 02-20-2018, 10:46 PM RE: Retro Review: BA-55 - martinot - 02-21-2018, 09:02 AM RE: Retro Review: BA-55 - Gene - 02-20-2018, 11:06 PM RE: Retro Review: BA-55 - Eddie W. Shore - 02-21-2018, 03:00 AM RE: Retro Review: BA-55 - martinot - 02-21-2018, 09:11 AM RE: Retro Review: BA-55 - Eddie W. Shore - 02-21-2018, 01:29 PM RE: Retro Review: BA-55 - martinot - 02-24-2018, 12:57 AM RE: Retro Review: BA-55 - Gene - 02-21-2018, 01:18 PM

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