ANOVA (ANALYSIS OF VARIANCE)
2024-01-19 4:20 PM
• ANOVAS usually used for hypothesis testing
EXAMPLE: we have 3 variables
1) Cheese
2) Candy
3) Fruit
Want to see what is the most popular snack.
SO WHAT NOW?
• We could do lots of pair-wise t-tests (compare 2
things at the same time)
Group 1 versus group 2
Group 1 vs group 3
Group 2 vs group 3
***but no, too easy
WHY NOT USE MULTIPLE T-TESTS?
1. THE PROBLEM OF TOO MANY T TESTS: FISHING FOR A FINDIN
2. PROBLEM OF TYPE 1 ERROR (ALPHA)
• New type 1 error rate = 1- (1-alpha) * comparisions (to the po
• We want type 1 error rate to stay at .05
**remember, type 1: rejecting the null when the null is true (findin
THE PROBABILITY OF A TYPE
2024-01-19 4:20 PM
• ANOVAS usually used for hypothesis testing
EXAMPLE: we have 3 variables
1) Cheese
2) Candy
3) Fruit
Want to see what is the most popular snack.
SO WHAT NOW?
• We could do lots of pair-wise t-tests (compare 2
things at the same time)
Group 1 versus group 2
Group 1 vs group 3
Group 2 vs group 3
***but no, too easy
WHY NOT USE MULTIPLE T-TESTS?
1. THE PROBLEM OF TOO MANY T TESTS: FISHING FOR A FINDIN
2. PROBLEM OF TYPE 1 ERROR (ALPHA)
• New type 1 error rate = 1- (1-alpha) * comparisions (to the po
• We want type 1 error rate to stay at .05
**remember, type 1: rejecting the null when the null is true (findin
THE PROBABILITY OF A TYPE
