AVEDEV

[Patrick Durusau <patrick@durusau.net>]

Greetings!

Lest we get too focused on the financial functions, can anyone tell me 
what is wrong with the following?

AVEDEV - Calculates the average of the absolute deviations of the values 
in list.

Yes, it should read, "the values in *a* list." but that's just poor 
writing and I can fix  that.

What else is problematic about this function and its definition in 
OpenFormula?

*****

Spoiler space












*****

Excluding the math formula, our text in full reads:

> *Summary:* Calculates the average of the absolute deviations of the 
> values in list.
>
> *Syntax:* AVEDEV( { /NumberSequenceList/ N }^+ )
>
> *Returns:* Number
>
> *Constraints:* None.
>
1) Average - not defined.

2) Absolute deviation - not defined

3) Values - not defined (what is the standard deviation of string 
values, one from the other?)

4) Values or NumberSequenceList?

5) Calculates - not defined

6) Calculates as opposed to return, returns, compute, computes, finds?

7) No constraints? Suspect that values being numbers (see #8 on present 
lack of definition) is one but see #4.

8) Returns Number? (Recalling that number is "defined" as "A number is 
simply a numeric value such as 0, -4.5, or $1000." That's an 
illustration, not a definition. So, when I apply AVEDEV to a list of 
numbers, an application could return a monetary amount? Granting that 
might make sense if the input was a series of monetary amounts but I 
don't see a limitation here that prevents a string of integers having an 
AVEDEV result of $42.

Not to exclude the math formula even though I am not including it in 
this email:

Math Formula

9) In order for this to be useful, simply reproducing it is 
insufficient. Formulas are defined to be useful assuming particular 
inputs and ranges on those inputs. As well as outputs. We don't have to 
keep repeating them but we do need to define those inputs, limits and 
outputs.

10) What precision required is not specified (not really the fault of 
the equation but seemed appropriate to mention here).

Note that fixing many of these issues for AVEDEV fixes the same issue 
for other functions.

This should not be seen as being discouraging. The hard part, deciding 
what needs to be defined and gathering up an enormous amount of 
information on each part has already been done. Plus we are close enough 
to say what remains to be defined to fully specify the functions in 
OpenFormula.

Hope everyone is having a great holiday season!

Patrick

-- 
Patrick Durusau
patrick@durusau.net
Chair, V1 - US TAG to JTC 1/SC 34
Convener, JTC 1/SC 34/WG 3 (Topic Maps)
Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)