Standard Deviation. Explain.

Skybird · 10-26-14, 08:14 PM

Quote:

Originally Posted by StdDev

The average amount by which a data point (ie score) deviates from the average of that same set of data points.

or it could mean how twisted the average person actually is

Or in other words: the amount of dispersion (Streuung) of scores from the expected value (Erwartungswert).

One of several additional descriptive values without which any expression of mean values (averages) usually makes little sense.

Started statistics courses?

vanjast · 10-27-14, 01:49 AM

Grouping accuracy

ikalugin · 10-27-14, 01:51 AM

I remember when I was doing my physics lab work stuff and my values (with accounted observation error) did not fit the -true- values I should have been getting.

And then I have used Student's coefficient of 0.99 hehe.

Eichhörnchen · 10-27-14, 02:21 AM

Quote:

Originally Posted by Skybird

Or in other words: the amount of dispersion (Streuung) of scores from the expected value (Erwartungswert).

One of several additional descriptive values without which any expression of mean values (averages) usually makes little sense.

Started statistics courses?

That's easy for you to say; for me it means something quite different...

ikalugin · 10-27-14, 02:23 AM

If you are doing it as a part of A-level math statistics course then just memorise the formula.

In layman terms (not a strict or even formally correct deffenition) - SD is how spread your values are, so the higher SD shows you a more chaotic rather than ordered spread of values.

Skybird · 10-27-14, 06:15 AM

Quote:

Originally Posted by Eichhornchen

That's easy for you to say; for me it means something quite different...

Hm...?

Jimbuna · 10-27-14, 07:07 AM

The position Todd took at the cafe that night in Houston when the weirdo asked him for a cigarette

Gargamel · 10-27-14, 08:19 AM

The square of the variance

.... or is it square root?

In poker we used to call it a measure of short term luck.

Jeff-Groves · 10-27-14, 08:38 AM

Quote:

Originally Posted by Skybird

Started statistics courses?

Nope. Writing a program that captures data from a chronograph then calculates the SD and other stuff interesting to Air Gunners.
Found a simple example here:

http://www.mathsisfun.com/data/stand...-formulas.html

The written formula may as well be Chinese to me.

Sailor Steve · 10-27-14, 09:08 AM

Quote:

Originally Posted by Gargamel

.... or is it square root?

Not a square knot?

Quote:

Originally Posted by Jeff-Groves

The written formula may as well be Chinese to me.

Ask Rhodes. It's all Greek to him.

Chad · 10-27-14, 10:32 AM

What language are you writing your application in? Some core languages may already have a function for calculating standard deviation in its Math library class.

If not, pending the language, I could try writing up a small method.

Eichhörnchen · 10-27-14, 11:25 AM

this?

Jeff-Groves · 10-27-14, 02:13 PM

Quote:

Originally Posted by Chad

What language are you writing your application in? Some core languages may already have a function for calculating standard deviation in its Math library class.

If not, pending the language, I could try writing up a small method.

VS 2008 C++ is what I use.
It has no StDev function so I'll have to search out some code or do it myself.
I'm not big into adding other stuff like Boost etc.
FLTK 1.3.2 is all I have and that's for GUI work.

Aktungbby · 10-27-14, 02:49 PM

^

I see it so clearly now; Jeff! You've got it in a nutshell!

I didn't know air guns were so complicated.

ikalugin · 10-27-14, 03:16 PM

Err you don't really need to create an object (class) for this, a simple function should do just fine.

10-27-14, 07:07 AM	#7
Jimbuna Chief of the Boat Join Date: Feb 2006 Location: 250 metres below the surface Posts: 190,526 Downloads: 63 Uploads: 13	The position Todd took at the cafe that night in Houston when the weirdo asked him for a cigarette __________________ Wise men speak because they have something to say; Fools because they have to say something. Oh my God, not again!!

10-27-14, 08:19 AM	#8
Gargamel Lucky Sailor Join Date: Oct 2010 Location: Rome Posts: 4,273 Downloads: 81 Uploads: 0	The square of the variance .... or is it square root? In poker we used to call it a measure of short term luck. __________________ Luck is a residue of Design.

10-27-14, 10:32 AM	#11
Chad ACE Join Date: Sep 2002 Location: Kansas City Posts: 1,274 Downloads: 60 Uploads: 0	What language are you writing your application in? Some core languages may already have a function for calculating standard deviation in its Math library class. If not, pending the language, I could try writing up a small method. __________________

10-27-14, 11:25 AM	#12
Eichhörnchen Starte das Auto Join Date: Aug 2014 Location: The Fens Posts: 17,388 Downloads: 5 Uploads: 0	Why would you need that, when you've got this?

10-27-14, 02:49 PM	#14
Aktungbby Gefallen Engel U-666 Join Date: Jul 2013 Location: On a tilted, overheated, overpopulated spinning mudball on Collision course with Andromeda Galaxy Posts: 30,006 Downloads: 24 Uploads: 0	That's not mean deviation-that's CRUEL deviation! ^ I see it so clearly now; Jeff! You've got it in a nutshell!I didn't know air guns were so complicated. __________________ "Only two things are infinite; The Universe and human squirrelyness?!!

10-27-14, 01:49 AM	#2
vanjast Sea Lord Join Date: Jun 2006 Location: Somewhere else now Posts: 1,734 Downloads: 825 Uploads: 4	Grouping accuracy

10-27-14, 01:51 AM	#3
ikalugin Ocean Warrior Join Date: Aug 2014 Location: Moscow, Russia Posts: 3,212 Downloads: 8 Uploads: 0	I remember when I was doing my physics lab work stuff and my values (with accounted observation error) did not fit the -true- values I should have been getting. And then I have used Student's coefficient of 0.99 hehe.

10-27-14, 02:23 AM	#5
ikalugin Ocean Warrior Join Date: Aug 2014 Location: Moscow, Russia Posts: 3,212 Downloads: 8 Uploads: 0	If you are doing it as a part of A-level math statistics course then just memorise the formula. In layman terms (not a strict or even formally correct deffenition) - SD is how spread your values are, so the higher SD shows you a more chaotic rather than ordered spread of values.

10-27-14, 03:16 PM	#15
ikalugin Ocean Warrior Join Date: Aug 2014 Location: Moscow, Russia Posts: 3,212 Downloads: 8 Uploads: 0	Err you don't really need to create an object (class) for this, a simple function should do just fine.