Measures of Significance

c² (Chi-square) Measure of Significance

Measures the statistical significance of a relationship in a table.
It compares the observed relationship to what would be observed if the null hypothesis were true (i.e. there really isn't a relationship).

Through its reported probability value, it tells you the likelihood that you would find the observed relationship, if the null hypothesis were really true for the population.

That is, how likely is it that this relationship we found is simply due to sampling error?
Or, how probable is it, given our findings, that the null hypothesis is really true?

A probability value of less than .05 is the social science standard for rejecting the null hypothesis.
This logic also applies to the probability values associated with other measures of significance.

The important thing to remember is that the probability value given represents the probability that the null hypothesis is true for the population. (i.e. the probability that there really is no relationship between these two variables)

NOTE: Chi-square is not a measure of the strength of a relationship. All it does it tell you is you can infer this relationship to the population.
Three factors influence the value of Chi-square:

The strength of the relationship
The size of the sample
The size of the table