Chapter 13 Test for Goodness of Fit Chi Square, 2,Goodness of Fit is a test that checks to see if observed counts from a sample are significantly different than an expected (standard) value Chi Square distributions are all right skewed and their actual shape depends on their degrees of freedom (one less than the number of categories)

Again the larger the sample size, the closer the distribution comes to being normal.

Assumptions/Conditions: If the chi square value is large the corresponding P-value is small and indicates significance. Assumptions/Conditions: SRS All expected counts are at least 5 Independent observations, 10% condition if sampling without replacement (N > 10n)

Chi Square Steps State Ho and Ha Calculate expected values (multiply total observations by stated percentages) Calculate (O-E)2/E for each category Add up that column to get 2 value After doing the test, always do a follow-up analysis of the data with a graph. Homework page 710 problems 1,3,4