Questions (1)
        What are main effects in ANOVA? 
        What are interactions in ANOVA?  How do 
          you know you have an interaction? 
        What does it mean for a design to be 
          completely crossed?  Balanced?  
          Orthogonal? 
        Describe each term in a linear model like 
          this one:  
        y    () e
         ijk     j   k      jk  ijk
           Questions (2)
            Correctly interpret ANOVA summary 
               tables.  Identify mistakes in such 
               tables.  What’s the matter with this 
               one? 
           Source SS        Df              MS  F
           A       512      2 (J-1)         128    128
           B       108      1 (K-1)         108    54
           AxB     96       2 (J-1)(K-1)    48     24
           Error   12       5 N-JK          2
     Questions (3)
      Find correct critical values of F from a table 
      or software for a given design. 
      How does post hoc testing for factorial 
      ANOVA differ from post hoc testing in one-
      way ANOVA? 
      Describe a concrete example of a two-factor 
      experiment.  Why is it interesting and/or 
      important to consider both factors in one 
      experiment? 
               2-way ANOVA
               • So far, 1-Way ANOVA, but can have 2 
                  or more IVs.  IVs aka Factors.
               • Example:  Study aids for exam
                   –IV 1:  workbook or not
                   –IV 2:  1 cup of coffee or not
                                       Workbook  (Factor A)
                       Caffeine        No              Yes
                       (Factor B)
                       Yes             Caffeine only   Both
                       No              Neither         Workbook 
                                       (Control)       only
           Main Effects (R & C means)
             N=30 per    Workbook (Factor A)        Row 
             cell                                   Means
             Caffeine    No             Yes
             (Factor B)
             Yes         Caff           Both        82.5
                            =80             =85
                         X              X
                         SD=5           SD=5
             No          Control        Book        77.5
                             =75            =80
                         X              X
                         SD=5           SD=5
             Col Means   77.5           82.5        80