Exam 2 - 1 of 4 ID# Exam 2 PS 217, Fall 2009 As always, the Skidmore Honor Code is in effect, so at the end of the exam you will need to sign a sheet attesting to your adherence to the code. Read each question carefully and answer it completely. Be sure to show all your work, otherwise I cannot give you partial credit for your work. Remember to think of a point as a minute, so you should expect to spend roughly 15 minutes on a 15-point question, etc. If a question is unclear to you, be sure to ask me for clarification. Good luck on the exam. 1. Dr. Ty Pest is a human factors psychologist who is interested in testing the impact of different keyboard layouts on typing speed. To that end, he chooses four different conditions: a normal keyboard with normal (QWERTY) keyboard layout, a normal keyboard with the Dvorak layout of keys (supposedly a more efficient layout), an ergonomic (split) keyboard with normal keyboard layout, and an ergonomic (split) keyboard with the Dvorak layout of keys. His participants are ten secretaries who have at least 5 years of typing experience. The DV is the number of words per minute of typing of complex textual material in 15 minutes. Below are the incomplete analyses of his experiment. Complete the analyses and interpret the results as completely as you can. [15 pts] Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Powera Keyboard Sphericity Assumed 11787 .000 .975 1.000 Error(Keyboard) Sphericity Assumed 308Exam 2 - 2 of 4 2. Dr. Justin Case was interested in determining if temperature had an impact on performance on a quiz. He took a class of 100 statistics students and randomly assigned a quarter of the class to a room where the temperature was 50°, another quarter was assigned to a room where the temperature was 70°, another quarter was assigned to a room where the temperature was 80°, and the final quarter was assigned to a room where the temperature was 100°. The students all took the same quiz (max.score = 10). Using the summary data below, conduct as complete an analysis of this experiment as you can, then provide a detailed interpretation of the results of the experiment. [15 pts] 50° 70° 80° 100° T (ΣX) 175 215 200 185 G = 775 Mean 7.0 8.6 8.0 7.4 ΣX2 = 6331 SS 127 36 67 58Exam 2 - 3 of 4 3. Suppose that in the not-too-distant future you conduct a single factor experiment using a repeated measures design, but you can't remember how to perform a repeated measures ANOVA. All you can remember from your PS217 class is how to conduct an independent groups ANOVA, so you go ahead and analyze the data from the repeated measures design using an independent groups ANOVA. Your analysis is significant (i.e., you can reject H0). Even though you've conducted an inappropriate analysis, would you be inclined to believe the results of your analysis? Why or why not? Under which circumstances might you be disinclined to believe the results of your analysis? [10 pts] 4. Suppose that you’ve analyzed a set of data from an experiment as a repeated measures ANOVA. You’ve obtained F(3,12) = 5. Your MSError = 1 and there are 5 scores in each condition. Now, however, you find out that you should have computed an independent groups ANOVA. Fill in the source table below as it should appear with the appropriate analysis (i.e., assuming that all the scores are the same). [Hint: Pay attention to the df. If you’re confused, first try to construct as much of the repeated measures source table as you can.] [5 pts] Source SS df MS F Between Within Total 47Exam 2 - 4 of 4 5. A researcher studying the impact of caffeine on life expectancy adds two types of caffeine (i.e., found in coffee and chocolate) to the water supply of groups of laboratory-bred rats. This species typically survives about 13 months. The water supply of a control group of rats did not have any caffeine added. The DV is the number of days that each rat lives. Analyze the results of this experiment as completely as you can. What would you do next? [10 pts] Coffee Caffeine Chocolate Caffeine No Caffeine 398 401 412 379 420 386 423 413 394 389 396 409 418 406 415 383 410 401 387 406 394 390 409 398 ANOVA dayslive Sum of Squares df Mean Square F Sig. Between Groups 277.2 .162 Within Groups 2927.6
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