Math Is Fun Forum

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Chi-Square Test

Have finished Chi-Square Test and Chi-Square Calculator

Please cast your eyes over them both, and let me know any errors or improvements so visitors get the best possible experience.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Chi-Square Test

Hi MIF;

Your examples work out and the page is good but I have a question:

This test only works for categorical data (data in categories), such as Gender {Men, Women} or color {Red, Yellow, Green, Blue} etc, but not numerical data such as height or weight.

I have used chi square on other than categorical data, for instance, testing the validity of a die by rolling it 6000 times and counting up the number of times 1 to 6 comes up. Say that the answer looks like this,{900,1100,1200,1000,900,900} you can calculate a p value for this to see whether or not this result could be by chance or not. So, does the quote still apply to n x 1 data? Would you consider my data as categorical?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,425

Re: Chi-Square Test

Hi MathsIsFun,

The pages Chi-Square Test and Chi-Square Calculator are well made! Thanks!

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It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Chi-Square Test

Thanks guys!

bobbym - did you compare {900,1100,1200,1000,900,900} to {1000,1000,1000,1000,1000,1000} ? Otherwise Chi-square is 0 (and DF 0 also)

If so I get a Chi-square of 38.7332 and p = 2.68247e-7 , which is quite cool as it shows that to be a very expected result.

So, we can agree here to give them honorary categories of test1 to test6 and random vs boring.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Chi-Square Test

Hi MIF;

Yes, I would compare them to {1000,1000,1000,1000,1000,1000}. Thanks for the explanation.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

mathaholic

Member

From: Earth

Registered: 2012-11-29

Posts: 3,251

Re: Chi-Square Test

That was kind of nosebloodening (hard for me to understand). But... Thanks for the info!

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