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**panicoschr****Member**- Registered: 2013-02-24
- Posts: 11

Hello. Can someone help me on this ?

Is it possible to calculate Standard Deviation for points distrubuted in 3-axis?

X Y Z.

Thanks

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

Hi;

Welcome to the forum. You could get the standard deviation of the x's, then the y's and then the z's.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

Standard deviation like a mean works on a list of elements not on 3 at a time.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

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**panicoschr****Member**- Registered: 2013-02-24
- Posts: 11

Hello again

i have another issue, if you could assist.

I have an array of integers from 0 - 250 positions, each one containing an integer. Is it possible to get a single value for this array, so that I can tell the difference between this array and other future arrays? Perhaps an integral?

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

There are several ideas but I would need to know a little bit more.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

Hi;

You are saying that you are using an array to keep track of 251 colors. You are assigning each box to a color and incrementing it by one each time you find one?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

Okay, what are you trying to do with that? Do you have some other array to compare it to?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**panicoschr****Member**- Registered: 2013-02-24
- Posts: 11

it would be easy to compare it with another array, slot by slot. But i want to get a value out of each array. Thinking of the array as a graph-> can i get a value out of it? area perhaps?distance of the area from 0? perhaps 2 or 3 small areas on a graph separated by 0 color values? sorry i can not think anything to compare 2 graphs that may look completely different.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

You want to turn the array into a single number? This could very well take much more time than comparing them element by element.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**panicoschr****Member**- Registered: 2013-02-24
- Posts: 11

can i do this, turn it to a number?

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

You are using some programming language?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**panicoschr****Member**- Registered: 2013-02-24
- Posts: 11

yes I am using C++ in eclipse.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

Does the new C++ have multiprecision arithmetic yet?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**panicoschr****Member**- Registered: 2013-02-24
- Posts: 11

I don't know what is this.

But i know it has fields like float and double.

*Last edited by panicoschr (2013-03-21 03:54:25)*

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

It still only has 16 digits of precision is what I mean. Basically that means only 16 digits in any number.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

No, not exactly. Remember order counts in your array so you just can't add up the numbers or multiply them. The simplest thing of course is the decimal system. How high are the numbers in the each array?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**panicoschr****Member**- Registered: 2013-02-24
- Posts: 11

sorry i had to leave for some time. I made a small testing , saw max no = 160. Of course most of the slots are value 0. Lets say only 30 slots have a value {3,4, 10 , 20 , 34 etc)

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 102,304

Hmmm, that is going to be a problem.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

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**DeanPemberton****Member**- From: USA
- Registered: 2014-10-30
- Posts: 20
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Standard deviation is a quantity calculated to indicate the extent of deviation for a group. I don't think it will work for points distributed in 3-axis.

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