6. The Chi-Squared Test

What are the conditions for the use of the chi-squared test?

Conditions for the use of the chi-squared test=

• nominal data in categories (at least 20 ppts)

• Test of difference and association

• independent groups ( in a test of difference)

• non parametric over a parametric test

(non- directional hypothesis here but could be done on either)

What is example of using the contingency table for the chi-squared test?

How to calculate the degrees of freedom?

To calculate the degrees of freedom (df)= (number of rows -1) x (number of columns - 1)

e.g a 2×2 table would be:

(2-1)x(2-1)= 1= df

How to calculate the chi-squared value?

the chi-squared value is the [(E-O)²/E] values all added up together

e.g for the contingency table example above= .6 + .4 + .6 +.4= 2 → chi squared value (X²)

What must the calculated value of X ² be for significance?

Calculated value of X² must be equal to or more than the critical value in this table for significance at the level shown.

for the statement of significance for example above=

At a 5% probability level the calculated value (2) is less than the critical value (2.71) so there is no significant difference or association.. (“context of question.”) Any similarities or differences in the data occurred by chance; not due to the experiment