Help involving Chi squared test

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In summary, the conversation is about a person needing urgent help with a Chi squared test for their project. They are struggling with one of the rows having an expected value of zero, which they cannot divide by. Suggestions are made to either combine cells until every cell has an expected count above 5 or to try a different test. The person is unsure of how to combine rows and questions if the expected values were calculated correctly.
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mmmboh
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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!
 
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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.
 
  • #3


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.
 
  • #4


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!
 

What is a Chi squared test and when should it be used?

A Chi squared test is a statistical method used to determine whether there is a significant relationship between two categorical variables. It should be used when the data being analyzed is categorical and the researcher wants to determine if there is a significant difference between the observed and expected frequencies.

What are the steps involved in conducting a Chi squared test?

The first step is to state the null and alternative hypotheses. Next, the researcher must determine the appropriate test statistic based on the type of data being analyzed. Then, the observed and expected frequencies must be calculated. Finally, the test statistic is compared to the critical value from the Chi squared distribution to determine if the null hypothesis should be rejected or not.

What is the difference between a one-tailed and two-tailed Chi squared test?

A one-tailed Chi squared test is used when the researcher has a specific direction or prediction for the relationship between the variables. A two-tailed Chi squared test is used when the researcher does not have a specific direction or prediction and is simply looking for any significant relationship between the variables.

How can I interpret the results of a Chi squared test?

If the p-value is less than the chosen significance level, typically 0.05, then the null hypothesis can be rejected and it can be concluded that there is a significant relationship between the variables. If the p-value is greater than the significance level, then the null hypothesis cannot be rejected and it can be concluded that there is no significant relationship between the variables.

What are some limitations of the Chi squared test?

The Chi squared test assumes that the data being analyzed is independent and that the expected frequencies are greater than 5. If these assumptions are not met, the results of the test may not be accurate. Additionally, the Chi squared test can only determine if there is a significant relationship between the variables, but it cannot determine the strength or direction of the relationship.

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