Introduction to Statistics

 


Chi2 Test (goodness of fit)

X2 test is a test of distributions

Think of it as a way to compare histograms

You will compare one set of data to "what you expected to get"
 
 

Test statistic = X2 = Sum of (observed expected)2
                                                        expected

Look up the critical value

df = degrees of freedom = number of categories 1

Reject null hypothesis if X2 > critical value of X2