i. The number of degrees of freedom appropriate for the chi-square goodness-of-fit test is the number of categories minus 2.
Ii) If there are extremely large differences between observed and expected frequencies the correct decision is to reject H0.
Iii) There are 2 degrees of freedom for a contingency table classifying three levels of income with each gender.
A) (i), (ii) and (iii) are all correct statements
B) (i) and (ii) are correct statements, but not (iii).
C) (i) and (iii) are correct statements but not (ii).
D) (ii) and (iii) are correct statements but not (i).
E) All statements are false

Question

Quizplus · Accepted Answer

The degrees of freedom for a chi-square goodness-of-fit test is the number of categories minus 1, not 2, making statement (i) false. Statement (ii) is correct because large differences between observed and expected frequencies suggest rejecting the null hypothesis. Statement (iii) is correct because for a contingency table with 3 income levels and 2 genders, the degrees of freedom is (3-1)(2-1) = 2.

I the Number of Degrees of Freedom Appropriate for the Chi-Square