Help involving Chi squared test

  • Thread starter Thread starter mmmboh
  • Start date Start date
  • Tags Tags
    Chi Test
AI Thread Summary
When conducting a chi-squared test, encountering an expected value of zero is problematic because it leads to division by zero in the formula (O-E)²/E. A common solution is to combine categories or cells with low expected counts to ensure all expected values are 5 or greater, adjusting the degrees of freedom accordingly. If the expected value is calculated correctly and remains zero, it suggests that the corresponding category is invalid, necessitating its exclusion from the analysis. It's important to verify the calculations for row and column totals to avoid errors. Proper handling of expected values is crucial for accurate chi-squared test results.
mmmboh
Messages
401
Reaction score
0
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!
 
Physics news on Phys.org


mmmboh said:
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.
 


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.
 


mmmboh said:
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!
 

Thread 'Value of intuitionistic logic'

I'm taking a look at intuitionistic propositional logic (IPL). Basically it exclude Double Negation Elimination (DNE) from the set of axiom schemas replacing it with Ex falso quodlibet: ⊥ → p for any proposition p (including both atomic and composite propositions). In IPL, for instance, the Law of Excluded Middle (LEM) p ∨ ¬p is no longer a theorem. My question: aside from the logic formal perspective, is IPL supposed to model/address some specific "kind of world" ? Thanks.
View full post »

Thread 'Formal derivation of statement from Peano Arithmetic system'

I was reading a Bachelor thesis on Peano Arithmetic (PA). PA has the following axioms (not including the induction schema): $$\begin{align} & (A1) ~~~~ \forall x \neg (x + 1 = 0) \nonumber \\ & (A2) ~~~~ \forall xy (x + 1 =y + 1 \to x = y) \nonumber \\ & (A3) ~~~~ \forall x (x + 0 = x) \nonumber \\ & (A4) ~~~~ \forall xy (x + (y +1) = (x + y ) + 1) \nonumber \\ & (A5) ~~~~ \forall x (x \cdot 0 = 0) \nonumber \\ & (A6) ~~~~ \forall xy (x \cdot (y + 1) = (x \cdot y) + x) \nonumber...
View full post »

Similar threads

B Chi square test (two-sided vs. one-sided)
Replies
23
Views
2K
How to set up and interpret Chi^2 test results for my data?
Replies
11
Views
3K
I Does Returning Marbles After Each Draw Affect Chi-square Test Results?
Replies
8
Views
2K
B Chi-squared test stat choosing a critical value
Replies
5
Views
3K
I Small Reduced Chi Squared interpretation
Replies
5
Views
5K
A Interpreting Chi Squared .... backward
Replies
20
Views
4K
I About chi-squared and r-squared test for fitting data
Replies
5
Views
9K
Pearson's chi-square test versus chi-squared distribution
Replies
4
Views
3K
I How can I convert chi-square into a matrix and graph likelihood contours?
Replies
14
Views
3K
Question on Pearson's Chi-squared test
Replies
4
Views
2K

Hot Threads

Recent Insights

Back
Top