en:statpqpl:porown2grpl:nparpl:chikw

These tests are based on data collected in the form of a contingency table of 2 traits, trait X and trait Y, the former having and the latter categories, so the resulting table has rows and columns. Therefore, we can speak of the 2×2 chi-square test (for tables with two rows and two columns) or the RxC chi-square test (with multiple rows and columns)).

We can read the details of the chi-square test of the two features here:

**Basic assumptions:**

- measurement on a nominal scale - any order is not taken into account,

The additional assumption for the :

**General hypotheses:**

where:

– observed frequencies in a contingency table,

– expected frequencies in a contingency table.

Hypotheses in the meaning of independence:

The p-value, designated on the basis of the test statistic, is compared with the significance level :

**Additionally**

- In addition to the chi-square test, another related test may need to be determined. In the event that Cochran's condition is not satisfied, one can determine:

- If we obtain a table of Rx2, and the R categories can be ordered, it is possible to determine the trend:

- When significant relationships or differences are found based on a test performed on a table larger than 2×2, then multiple comparisons can be performed with appropriate correction of the multiple comparisons to locate the location of these relationships/differences. This correction can be done automatically when the table has many columns. In such case, in test option window you should select
`Multiple column comparisons (RxC)`

. - In the case where we want to describe the strength of the relationship between feature X and feature Y, we can determine:

- In the case when we want to describe for 2×2 tables the effect size showing the impact of a risk factor, we can determine:

Cochran W.G. (1952), The chi-square goodness-of-fit test. Annals of Mathematical Statistics, 23, 315-345

en/statpqpl/porown2grpl/nparpl/chikw.txt · ostatnio zmienione: 2022/02/11 21:20 przez admin

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