-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of David Firth
Sent: Saturday, January 05, 2002 3:28 PM
To: [EMAIL PROTECTED]
Subject: Stat Requirement (was Excel2000)
<thank you for your response>
Thanks for the wealth of Excel trivia. Use the right tool for the job, I
say.
Excel might not be it.
I do have to take a little offense to the accuracy remark regarding business
calcs -- I learned early on that bcd reals or integer-based math libs were
the only appropriate mechanisms for business calcs. I prefer not to use
regular
real/float types if I have alternatives. But I'm a measurement/data acq man.
We can be a bit, well, anal about accuracy.
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What I had in mind was that the variant form of data input in each cell (in
EXCEL, in VB and in VBA), accepts the following:
0 Empty No data/entry (once held something but now is blank).
1 Null No value. Unknown data.
2 Integer Whole number -32768 to +32767, 2 bytes.
3 Long Whole number (integer) -2,147,483,648 to +2,147,483,647, 4
bytes.
4 Single Floating point decimal number, aprox 7 decimal digits, 4 bytes.
5 Double Floating point decimal number, aprox 15 decimal digits, 8
bytes. -1.79769313486231E308 to
-4.94065645841247E-324 and +4.94065645841247E-324 to
+1.79769313486232E308
6 Currency Decimal number with 4 decimal places, 8 bytes, 19 digits max.
Use
it to minimize rounding errors.
-922,337,203,685,477.5808 to +922,337,203,685,477.5807
7 Date/time A number, the left integer portion representing days and the
right decimal portion representing time as a fraction of a day, 8
bytes
There are a number of functions that will extract calendar and time
information from it.
8 String Text. 10 bytes + string length, up to 2 billion characters.
However EXCEL limits cell contents to a maximum of 256
characters.
9 OLE Object 4 bytes.
10 Error Code number returned if an error in a computation occurred, 2
bytes.
11 Boolean True or false, 2 bytes. Integer, 0 is false, -1 is true.
12 Variant An array of variants, 16 bytes numbers, 22 bytes + string length
13 Non-Ole Object
14 Decimal 14 bytes. +/-79,228,162,514,264,337,593,543,950,335 with no
decimal point.
+/-7.9228162514264337593543950335 with 28 places to the right
of the
decimal.
Smallest non-zero number is +/-0.(27 0's)1
17 Byte 1 byte. 0 to 255.
8192 Array An ordered table of values
The number in the left column comes from the VarType() function. EXCEL uses
a separate formatting code to indicate how the number appears in the cell
(i.e. number of decimal points and % conversion). If I do calculations with
currency, I have up to 19 accurate digits, whereas with double, only 15. If
I do integer arithmetic with long integers, I only have up to 10 digits.
When you format a cell, EXCEL allows only 0, 1, 5, 6, 7, 8 and 11. Macros
can use all the other types. I have no experience with using decimal
numbers.
DAHeiser
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A CS program more aligned with the needs of science, business, or econ might
be found, but CS is a general thing. The idea is that with the help of
content
experts or reference books the capable CS grad could do good work. If the
programmers involved slapped out some code and then went roller skating
(apologies to Dilbert) then they didn't do a good job. My 11 years in the
software side of embedded systems has contained too many recommendations to
peers about spending time to understand the customer's needs.
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Bravo. Applause. (We will overlook the fact that the customer usually
doesn't know his needs until 2 weeks before product delivery date. This is
why software development is an involved time consuming interactive process.)
DAHeiser
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IMHO it is more
of a process issue than a knowledge base problem. I took stats as an
elective
when I was an electronics engr tech undergrad because I thought it would be
handy.
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Great, Good. Applause.
DAHeiser
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> From what I have observed, many business type have a very limited math
background, and even learning simple business stat is a major problem. For
example try getting them to understand the difference between using z and
t tests,
Yes, but the idea again is to be a generalist who makes use of content
experts. I am now in an MBA program and have found that if I want to delve
into stats I do it on my own. I do wish that I'd had more stats exposure in
my data analysis or econ coursework. "Stats for MBAs" would be great. Given
my software background, "Stats for programmers" would be even better.
When does the class start? ;)
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What has happened is that companies like Statsoft, SPSS, SAS (and others)
hire PhD's in stat to scour the literature (and research areas) for ideas
and algorithms that can be turned into sellable product. They translate them
to the programmers who develop the code. The look-and-feel is a joint work.
There aren't that many software developers that incorporate stat in their
product out there, so the market for stat savvy CS's is not that great.
DAHeiser
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--
Still thinking different: Newton 2100.
Posted with Ink Spot for Newton.
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