Two-Factor ANOVA handout #2 Psych248 Dr. Huselid A college is conducting a study of its students' expectations of employment upon graduation. Students complete a questionnaire on their perceived job preparedness to get an expectation score (0 to 30). Use ANOVA to test to see if Major and Year in school have any effect on job expectations. Raw data Humanities Sciences Business 1: Hypotheses - 3 sets for 3 tests: Freshmen 2 5 7 Factor A: 4 6 8 Factor B: 3 9 7 10 12 AxB Interaction: Sophomores 3 10 20 4 12 13 2: .05 Critical Values - 3 for 3 F-tests: 16 16 Factor A df: ( , ) CV = 5 14 15 Factor B df: ( , ) CV = AxB df: ( , ) CV = Hum. Sci. Bus. Factor A: Summary year in data school 3a: Calculations - SS stage 1 SSBG: Fresh. 7.5 8.5 16 30 34 TA1 Soph. M 4.5 13 16 SSw T 52 64 TAX SST: Factor B: TB1 TB2 TB3 G = 214 Major EX? = 2458 3b: Calculations - SS stage 2- for 3 F-tests: Factor A: Factor B: AxB Interaction:Two-Factor ANOVA handout #2 Psych248 Dr. Huselid Fill in SS from page 1. Fill in df's from formulas. Each MS is SS/df. 3 F's are MS for that factor / MSwithin or error ANOVA SUMMARY TABLE: Source SS df MS F Between Conditions SSA Major SSB Year SSAB (Interaction) Error - Within 99 18 5.5 Conditions Total 549.83 23 Which F's are significant? If F > CV its sig. CV for each F depend on df of factor Main effect A (major)? Y N CV major (2,18) = CV year (1,18) = Main effect B (year)? Y N CV AXB (2,18) = Interaction? Y N Write APA conclusion 1) report the test used and significance of each F using the IV and DV names. 2) report the pattern of the differences found (look at the M's) - focus on the pattern of the interaction if it is significant because it tells the full story of how the factors combined