Chi Squared Test Flashcards
what is the chi squared test?
the chi squared test can be a test of difference or a test of association
it deals with nominal (categorical) data
for each category, you count up the number of people or items in that category (frequency count)
data must be independent
reasons for choosing a chi squared test
the hypothesis states a difference or association between two sets of data
the data in each cell is independent
the data is nominal
how to complete a chi squared test
1) state hypothesis — either an alternative hypothesis (directional or nondirectional) or a null hypothesis
2) collect and place raw data in a contingency table — the number of people in each cell is recorded and totals for each row and column are calculated
3) find calculated value of x2 — add all the values in the final column to get the calculated value of x squared
4) find the critical value of x2 — using significance level 5%, identify the kind of hypothesis (one tailed test if directional and vice versa), identify the df value, locate the row in the statistical table that begins with your df level value, the number in the box is the critical value of x2
5) report the conclusion — if the calculated value is equal to or greater than the critical value, the result is significant
how to work out df value for chi squared test
(number of rows - 1) x (number of columns - 1)
