2-Way ANOVA

1
2-Way ANOVA

• Class Exercise

2
Hays (5th ed) p. 520

• A study involved children of three age groups
• A15yrs, A2 6 years, A3 7 years.
• Second Factor was formal preschool experience
• B1none, B21 year, B3 more than 1 year
• Five children were sampled from each combination
  and given a score on social maturity (high
  scores are more mature)

3
B1 B2 B3
A1 2 2 4
A1 6 7 8
A1 8 8 11
A1 10 8 5
A1 9 10 3
A2 7 6 9
A2 9 9 14
A2 11 9 15
A2 9 7 10
A2 8 8 12
A3 15 13 15
A3 12 12 18
A3 9 10 21
A3 10 6 10
A3 14 9 14
4
Enter the data into SAS

• Print the data to be sure they are correct
• Be sure the data are arranged in the way SAS
  needs to analyze the problem

5
Run a 2-Way ANOVA on the data

• What terms are significant
• What is the interpretation at the level of main
  effects and interactions from the printout?

6
Graph the means

• What is the interpretation of the means according
  to the graph?
• You can use a program other than SAS for the
  graph if you want.

7
What is the magnitude of effect

• What is R-square for A, B, and AB?
• What is estimated omega-squared for each?