Introduction:
It helps us understand if there's a relationship between two sets of data that fall into categories, like yes/no responses or different groups of people. It's like asking if there's a meaningful connection between what we're measuring.
Test Statistics
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where,
O = Observed frequency
E = Expected Frequency
Properties of Chi-Square Test
- All Chi-Square values are greater than or equal to Zero (0).
- The area under each curve of the chi-square distribution equals 1.
- The chi-square distribution is always positively skewed because it only produces positive values. This happens because the differences from expected values are squared, making sure that the values can't be negative. So, it's like a rule that keeps everything on the positive side.
- Chi-square values lie between 0 to 1.
Conclusion
The chi-square test helps us see if there's a meaningful connection between different categories of data. It's like a tool that tells us if there's a relationship or not, based on how much our actual observations differ from what we expected.