Help involving Chi squared test

[mmmboh]

URGENT help involving Chi squared test!

Hello, I am doing a chi squared test for a project due soon and everything is fine, except for one thing...for one of my rows the expected value is zero!...and the equation is (O-E)^2/E...but I can't divide it by zero because that will give infinity...so what do I do if the expected value is zero? not include it in the summation?...

Help is greatly appreciated!

 

[statdad]

Hello, I am doing a chi squared test for a project due soon and everything is fine, except for one thing...for one of my rows the expected value is zero!...and the equation is (O-E)^2/E...but I can't divide it by zero because that will give infinity...so what do I do if the expected value is zero? not include it in the summation?...

Help is greatly appreciated!

A common suggestion is to combine cells for which the expected count is below 5: pool cells until every cell has expected count >=5, then do the test. when you do this base the degrees of freedom on the number of cells after combination, not the original number.

you could also try a different test.

 

[mmmboh]

Hm I'm not quite sure I follow, I am just suppose to combine rows together? I don't think that would work in my case, and my expected values for any given row are low anyway...is there something else I can do?...I don't think there is an alternate test, at least not that we have been tought.

 

[aznshark4]

Hello, I am doing a chi squared test for a project due soon and everything is fine, except for one thing...for one of my rows the expected value is zero!...and the equation is (O-E)^2/E...but I can't divide it by zero because that will give infinity...so what do I do if the expected value is zero? not include it in the summation?...

Help is greatly appreciated!

unless one row total or column total is exactly 0, then the expected cannot be 0. is the expected calculated right?

expected=[row total]x[column total]/[table total]

if one of the totals indeed 0, then the category containing that is completely invalid!