Quiz #3 Homework #3 data q3hw3.savHere are data from a 2-condition between subjects design. Subjects were permitted to take as many practice trials as they wanted (which was observed and measured) and completed a test trial that was either very much like the practice task (familiar condition=1) or seemingly different (unfamiliar condition=2). The DV is a performance score. 1a. Complete an ANOVA comparing the performance by each group. F ___________ df ____, ___________ p __________ familiar mean _______ std _____ unfamiliar mean ______ std ______ N ________ n _______b. Get the univariate statistics for the number of practices variable mean = ______________ std = _______________c. Use regression to perform an analysis with task type (use dummy coding with “unfamiliar” as the comparison group – same coding convention as GLM) and practice (centered). R² _________ F ___________ df ____, ___________ p __________ Predictor r p (for r) b β p for (b & β)FamiliarityPracticeconstant (a)d. Use Regression to get a model that also includes the interaction of practice and familiarity. R² _________ F ___________ df ____, ___________ p __________ MSresidual _________ Predictor r p (for r) b β p for (b & β)FamiliarityPracticeFamiliarity * Practice Interactionconstant (a) Interpret r, b & apredictor termInterpretationFamiliarityrbPracticerbFamiliarity *Practice Interactionrbconstant (a)e. Test the contribution of the interaction by comparing the R²Δ when it is added R²Δ _________ FΔ ___________ df ____, ___________ p __________f. Use GLM to obtain a model with the original Familiarity variable as the IV (Fixed Factor) and practice as the “Covariate” – buildthe interaction term in the “Model” window (you won’t get the right answer unless you do!)For the “corrected model” F ___________ df ____, ___________ p __________ Predictor F p b p for bFamiliarityPracticeFamiliarity * Practice InteractionCorrected means familiar group ___________ unfamiliar group __________ d. Obtain the separate regression model for each groupGroup coded 1 (familiar) y’ = ________ practice + ____________ Group coded 2 (unfamiliar) y’ = ________ practice + ____________e. Plot the regression equation below (roughly) -- plot to +/- 2 std on the x axisi. Does the “familiarity effect” change from the ANOVA (1a) to the ANCOVA (1c) to the full model (1d)? How so? Which of the threeis most likely to describe the “true familiarity effect”? Why?j. Give a complete interpretation of the interaction model and the plot -- tell the
View Full Document
Unlocking...