HP50g SigmaDat

[Chris]

I just got an HP50g. I have been playing around with it and trying (I stress "trying") to store data in the "sigmaDAT" variable for stats.

The manual suggests that when I enter data in the MATRW I should just then store it to sigmaDat (STO SDAT) as if there's a simple key sequence that will do that.

However I cannot (and again I stress cannot) find any way to store something to the SigmaDat register.

I see where sigmaDAT is when I go to run the stats application but no way to store something in it.

I could store it to any other memory register, but the good folks at HP clearly state I should be able to store it to the sigmaDat register as if there is such a thing.

How do I do this?

[Han]

If you are in the default algebraic mode, then:
1. create a matrix of values (or a vector, depending on what sort of stats you plan to do) and press ENTER.
2. press the STO> key and you should see ANS(1)> on the command line (the 1 may be a different value); finish typing into the command line the following keystrokes: right-shift, SIN, right-arrow, backspace, backspace, alpha, alpha, D, A, T, ENTER

If you are in RPN mode:
1. create your matrix/vector and place it onto the stack
2. type in the variable name with the tic marks: ', right-shift, SIN, right-arrow, backspace, backspace, alpha, alpha, D, A, T, ENTER, STO>

[BruceH]

sigmaDAT is the reserved variable. STOsigma (accessed from the CATalog) stores into it; RCLsigma recall it to the stack. Sigma+ and sigma- add and remove data points to and from your data set.

[Dave Britten]

The original 48GX Stat menu is available on the 50g, but hidden for whatever reason. All the SigmaDAT operations are in the DATA submenu. To access it, use the following steps: 96 MENU

I would suggest making a small program out of that, and either adding it to your Custom menu, or to a User key binding (USER Right-Shift 5 being the obvious choice).

Better yet, just buy a 48SX or 48GX, which has a sane menu layout. ;)

Another related tip: You can, of course, store a matrix directly in SigmaDAT, but you can also store the name of another matrix variable into SigmaDAT. If it contains a name, then all stat operations will operate indirectly on that named variable. This makes it much easier to store and work with a few different sets of data in one directory. The matrix variable has to already exist, however, otherwise Sigma+ will simply create a new matrix and store it directly in SigmaDAT.

[Norris]

Here's another way to store something into SigmaDAT.

Go to the STAT menu with [right-shift] 5.

Pick the type of statistical analysis that you want. Let's say it's "1. Single-Variable Statistics". So you select that.

In the resulting form, the cursor will be in the first space in the upper left, which is "SigmaDAT".

If you've already stored your data in a matrix variable, press CHOOSE and select it. The matrix will be copied to SigmaDAT.

If you haven't entered your data yet, press EDIT to go to the Matrix Editor and enter your data. When you finish, the result will be stored in SigmaDAT.

[Hal Bitton in Boise]

If EDAT already exists, here is yet another, very simple way to store data into it (RPN mode)...


Put the matrix you want to store into EDAT on level 1 of the stack.


Call up the VAR menu and find the EDAT softkey by scrolling through the variables with NXT.


Press left shift (and release), then the EDAT softkey to store whatever is in level 1 into the EDAT variable. (This works with any variable).


You can of course review what's already in EDAT by simply pressing it's softkey. You can also use the stack to save/swap data sets into EDAT.

Best regards, Hal

[Dave Britten]

Yup, Left-Shift SigmaDAT is a convenient way to store new data, as long as the variable already exists (or you've added its name to a custom menu). If not, you have to use a different approach.

Also, if you're going to work with multiple data sets, I'd recommend using the technique I mentioned earlier, i.e. storing the names of other variables into SigmaDAT. This will safeguard against a stack-clearing mishap destroying any of your data, or user error while shuffling data between variables. Also, the CLSigma command will only delete SigmaDAT, and not the underlying matrix variable holding the actual data, offering another layer of protection.

As an example, I wrote some programs for recording drive times of different routes, where each route is stored in its own matrix variable. The program prompts for a route name with 3 TVARS TMENU ... INPUT, then converts the resulting input string to a name and stores it in SigmaDAT. Then the program uses either Sigma+, or stores the data point directly into a new matrix if the named variable doesn't exist yet. The analysis/plotting routines do pretty much the same thing, minus creating new matrices.

Incidentally, you can do this same indirection with CST for saving custom menus. For example, I keep my normal custom menu in CST.DEFAULT, then store 'CST.DEFAULT' in CST. From there, I create submenus by invoking other CST.whatever list variables with TMENU. Thus I don't have to worry about a program's injudicious use of MENU deleting my permanent custom menus.

The one other place I can think of where this works is EQ - you can store the name of an algebraic variable, or a list of such variables. (This works with both the standard solver and multiple-equation solver.)

These indirection features aren't particularly obvious on the 48GX and newer models - I don't think the manual mentions it - but the way the variable catalog system works on the 48SX makes it second nature.

[Chris]

Thanks! I was able to finally find it waaaay down the list on the CAT menu.

Amazingly inconvenient.

Another poster also noted to directly enter it from the STAT menu.

As much as I have loved HP calculators for the past 30 years I fear that the quality of the product itself is going downhill. I am sure the 50g is far more powerful than I will ever utilize but I equally fear that it is cheap construction and materials and there's no way it will be around 22 years later like my trusty 11C is.

Thanks for all the help on this!