P554 Statistics in Psych, Prof. Kruschke

P554 Statistics in Psychology, Prof. Kruschke
Homework for Ch. 3 (Part I). Due at beginning of class, Tu 16 Jan 2007.

General instructions. Please write your name and student ID at the top of every page you hand in. Please collate and staple your pages together. Please write clearly and thoroughly explain all your computations; an unannotated series of formulas that mysteriously ends up with the correct number will not be given full credit. When doing the homework, you are encouraged to use all resources at your disposal to the extent that they help you learn the material; nevertheless, you must write your own answers in your own words.

  1. (8 pts.) p. 126, # 9a. (Do not do part b.)
    (A.) Analyze the data by hand, using a 12-row table with columns SubjectID, Group, Score(=Y), Predicted YF, Predicted YR, (Y-predYF)2, and (Y-predYR)2. Sum appropriate columns to indicate EF and ER. Compute F, look up and report the appropriate critical values, and state your conclusion.
    (B.) Analyze the data in SPSS. Include the output tables with your homework. What more does the SPSS output tell you that was not in your by-hand analysis?

  2. (6 pts.) p. 128, #11a. (Do not do part b.)
    Do this in SPSS only. You might want to get the data from the CD file. (Notice that the answer to this is in the back of the book, so you can check that your SPSS analysis agrees.)

  3. (6 pts.)
    Consider the data from #10, p. 127. We are interested in whether the scores differed, on average, across the three experiments. Each experimental group contains 2 x 12 = 24 scores. Use SPSS to conduct a Oneway ANOVA on the three experiment groups. (Get the data from the CD file.) Include the SPSS output with your homework. Answer these questions: Is the restricted model significantly worse than the full model? In general, if the restricted model is not significantly worse than the full model, does that mean that the restricted model is true?