Experimental+Design+II


 * ** EDU7006-8 ** ||  ||
 * ** Quantitative Research Design ** || ** 4 Experimental Designs II ** ||
 * Steve: Thank you for your work on this assignment. I know that learning this material is not easy and it takes a lot of time to read the text, calculate the statistics, interpret the statistics, and to respond to the essay questions. **
 * Regarding content: You are doing very well with the Jackson questions, but some of your calculations are not correct for Q10, which then impacts other calculations and your interpretation of the data. However, I have given you as much partial credit as I could. The content of your essay responses is right on track, but some of your points were not quite clear (see my notes in your document for where this occurred) and I would have liked to see you provide more explanation in the last essay question. The instructions also indicate that you should use 3-5 journal articles to support your answers, which you did not do (I forgot to include that in my previous feedback, but this was the case for other assignments as well). If we count each of the problems/questions and subquestions as one, we can consider that there are 20 questions in this assignment. I will take off ½ point for Q10 (even though there were 5 parts, I will give you 4.5 out of 5 on that question), ½ point for Q19, and ½ point for not including journal articles so your content score would be: 18.5 out of 20, which would be 92.5%. **
 * Regarding writing: I tried to give you more writing feedback in this paper so that you would see why I give the writing scores that I do. I will give you a 93% for writing here, which is the highest that I think I can give based on the issues and inconsistencies that I see in your writing. Please see my comments and edits throughout your document for details on writing issues in this paper. **
 * I hope that you are not discouraged by my evaluation of this assignment. Graduate work should be very challenging and, based on what I see in your work, I think you are up for the challenge and have the capacity to improve your work. **
 * Please note that individual faculty mentors do not have the ability to design or change the course or syllabus. Courses are designed and updated by a team of core faculty members and instructional designers. I encourage you to provide comments and suggestions about the syllabus and the course in the post-course survey if you feel that instructions are not matching instructor expectations in these courses. Thanks! **
 * Please note that individual faculty mentors do not have the ability to design or change the course or syllabus. Courses are designed and updated by a team of core faculty members and instructional designers. I encourage you to provide comments and suggestions about the syllabus and the course in the post-course survey if you feel that instructions are not matching instructor expectations in these courses. Thanks! **

=Experimental Designs II =

Jackson (2012) Chapter Exercises
**#2.** A 4 x 6 factorial design has two independent variables; the first with four levels and the second with six. A 4 x 6 factorial design has 24 conditions. **#4.** A cell mean represents the average score of participants in a condition, where a specific value of each independent variable interacts. Main effect means represent the average score of participants for a single independent variable, where no interaction with other independent variables are considered. **#6.** In a complete factorial design comparisons are made between each level of all independent variables with each level of every other independent variable. An incomplete factorial design is considered incomplete because comparisons are not made between each level of all independent variables with each level of every other independent variable; some comparisons are not made ( Jackson, 2012 ). **#8.** The number associated with the //way// of the ANOVA identifies the number of independent variables. A two-way ANOVA is an analysis of variance with two independent variables. A three-way ANOVA is an analysis of variance comparing three independent variables. **#10b1.** The first study is a 2 x 3 factorial design and has six conditions. **#10c1.** In the first study there were 36 participants in the six conditions. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#10d1.** In the first study, factor A was the only significant main effect accounting for approximately 15% of the variance, while there was also a significant interaction effect between factor A and B accounting for approximately 23% of the variance, both at the p < .01 level. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#10b2.** The second study is a 3 x 4 factorial design and has 12 conditions. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#10c2.** In the second study there were 84 participants in the 12 conditions. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#10d2.** In the second study, the only significant main effect was factor B, accounting for approximately 15% of the variance at the p < .05 level, while the interaction effect between factors A and B accounting for approximately 37.5% of the variance, is significant at the p < .01 level.* <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#10b3.** The third study is a 2 x 2 factorial design and has four conditions. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#10c3.** In the third study there were 40 participants in the four conditions. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#10d3.** In the third study there is no significant interaction effect between factors A and B and the only significant main effect was factor B, accounting for approximately 40% of the variance at the p < .01 level. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#12b.** Gender, F(1,24) = .02, not significant; <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">Practice <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">, F(2,24) = 60.26, p < .01; Gender x Time, F(2,24) = .03, not significant. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#12c.** Gender and the interaction of gender and practice time do not affect reaction time, but the main effect of practice time significantly affects reaction time.* <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#12d.** The effect size (η2) is 0.833, meaning that approximately 83% of the variance regarding reaction time is attributable to the amount of practice time. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**#12e.** [image in the Word file]
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">#10.* **
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">SOURCE ** || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">df **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">SS **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">MS **// ||  || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">F **// ||   || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.05 ** || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.01 ** ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor A ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">60 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">60 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(1, 30) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">9 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">4.17 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">7.56 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor B ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">40 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">20 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(2, 30) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.32 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">5.39 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">A x B ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">90 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">45 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(2, 30) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">6.75 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.32 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">5.39 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Error ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">30 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">200 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">6.667 ||  ||   ||   ||   ||   ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Total ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">35 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">390 ||  ||   ||   ||   ||   ||   ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> #10a1. ** <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">For the first study, Factor A, F(1,30) = 9.00, p < .01; Factor B, F(2,30) = 3.00, not significant; Interaction between A x B, F(2,30) = 6.75, p < .01.
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">SOURCE ** || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">df **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">SS **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">MS **// ||  || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">F* **// ||   || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.05 ** || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.01 ** ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor A ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">40 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">20 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(2, 72) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.15 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">4.98 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor B ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">60 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">20 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(3, 72) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2.76 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">4.13 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">A x B ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">6 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">150 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">25 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(6, 72) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.75 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2.25 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.12 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Error ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">72 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">150 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2.083 ||  ||   ||   ||   ||   ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Total ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">83 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">400 ||  ||   ||   ||   ||   ||   ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> #10a2. **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">For the second study, Factor A, F(2,72) = 3.00 not significant; Factor B, F(3, 72) = 3.00, p < .05; Interaction between A x B, F(6.72) = 3.75, p < .01.
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">SOURCE ** || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">df **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">SS **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">MS **// ||  || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">F* **// ||   || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.05 ** || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.01 ** ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor A ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">10 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">10 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(1, 36) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1.50 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">4.17 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">7.56 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor B ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">60 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">60 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(1, 36) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">9.00 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">4.17 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">7.56 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">A x B ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">20 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">20 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(1, 36) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.00 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">4.17 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">7.56 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Error ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">36 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">60 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1.667 ||  ||   ||   ||   ||   ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Total ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">39 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">150 ||  ||   ||   ||   ||   ||   ||
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">#10a3. **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">For the third study, Factor A, F(1, 36) = 1.50 not significant; Factor B, F(1,36) = 9.00, p < .01; Interaction between A x B, F(1,36) = 3.00 not significant.*
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">#12a. **
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">SOURCE ** || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">df **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">SS **// || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">MS **// ||  || //**<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">F **// ||   || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.05 ** || **<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.01 ** ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor A - gender ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.027 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.027 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(1, 24) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.023 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">4.26 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">7.82 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Factor B - **<span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">practice **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">* ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">140.600 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">70.3 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(2, 24) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">60.257 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.40 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">5.61 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">A x B ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">2 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.073 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.0365 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">F(2, 24) = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">0.031 || <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fcv = || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">3.40 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">5.61 ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Error ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">24 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">28.000 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">1.167 ||  ||   ||   ||   ||   ||
 * **<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Total ** || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">29 || <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 120%; text-align: right;">168.700 ||  ||   ||   ||   ||   ||   ||

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Assignment Question Answers
<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**Explain the difference between multiple independent variables and multiple levels of independent variables. Which is better?** Multiple independent variables allow the researcher to conduct more complicated experiments; manipulating multiple variables and determining the effect of each independently as well as the interaction between each variable.* Multiple levels <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">of independent variables <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> allow the researcher to assess each independent variable more completely with multiple treatments or conditions. These operations are not mutually exclusive. An experiment with multiple independent variables could have one or more independent variables with multiple levels. Both <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">multiple independent variables and multiple levels of independent variables <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> allow the researcher to get more information from a single experiment while keeping the number of participants low. Whether one is better than the other depends on what the researcher is attempting to discover from the study. If the researcher is seeking to better understand the behavior of a single factor then a multiple level independent variable is better. If the researcher believes that a behavior is caused by several factors <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">, <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> or the interaction between those factors <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">, <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> then a multiple independent variable design is better. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">What is blocking and how does it reduce “noise”? What is a disadvantage of blocking? Blocking is a technique whereby subjects are divided into “ <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 120%;">relatively homogeneous subgroups <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">” ( <span style="font-family: 'Times New Roman',Times,serif; font-size: 90%;">Trochim & Donnelly, 2008, p. 198 <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">). Noise consists of the extraneous factors that can make it difficult to determine effects in the real world. Blocking reduces noise and strengthens the treatment effect by minimizing the variability between subjects in each block. The disadvantage of blocking is that if, after the division, the subgroups are not homogeneous; variability increases, decreasing the ability of the researcher to determine effect. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**What is a factor? How can the use of factors benefit a design?** A factor is a variable. By using more than one independent variable in a design, researchers are able to determine the effect of each independent variable, known as a main effect, as well as the effects of the interactions between the variables, or interaction effects. Using a factorial design enables the investigator to conduct research that mirrors the real world more accurately. <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">(Than what?) <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**Explain main effects and interaction effects.** Main effects depict the consequences of a single independent variable in isolation from other independent variables in a factorial design. Interaction effects depict the results of the combining of two or more independent variables. In these interactions <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">, <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> the researcher may determine what outcomes are attributable to each variable at various levels of other variables. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**How does a covariate reduce noise?** A covariate is a variable that is adjusted in a study so as to remove its affect on the independent variable. This adjustment is done statistically. By removing the affect of the covariate, the effect of the independent variable remains,* but the variability due to the covariate is removed, resulting “ <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 120%;">in a more efficient and more powerful estimate of the treatment effect <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">” ( <span style="font-family: 'Times New Roman',Times,serif; font-size: 90%;">Trochim & Donnelly, 2008, p. 201 <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">). <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">**Describe and explain three trade-offs present in experiments.** The one constant of experiments is the use of randomization <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">to <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> assign subjects to condition groups ( <span style="font-family: 'Times New Roman',Times,serif; font-size: 90%;">Wiley, 2009 <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">). All other decisions with regards to design involve trade-offs; <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">selecting <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> one design has both advantages and disadvantages. Once a design is determined, the appropriate statistical analysis is chosen. This analysis is conducted following the collection of data. The largest trade-off of an experiment regards internal versus external validity.* An experiment is about control. The purpose of an experiment is to keep all conditions equivalent except for the manipulation of the independent variable. This does not necessarily work well in the real-world. If the researcher succeeds in this control, <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">the <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> internal validity of the experiment is very high and cause and effect determined, while external validity may be very low since the results may not be generalizable outside of the experimental conditions. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">The number of participants available <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">for <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">a study* poses a trade-off to the research designer. A simple design will generally require fewer participants than will a more complex design, but complex designs are able* to determine interactions and effects that are more consistent with the real-world, increasing external validity while maintaining internal validity. Wiley (2009) acknowledged three trade-offs regarding sample size; (a) larger <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">sample <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> sizes allow for discovering small effects but increases time and expense, (b) larger <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">sample <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;"> sizes in a highly human interactive experiment may increase more variability than the effects discovered,* and (c) larger sized samples are less likely to <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">show <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">large differences between groups, but are unlikely to eliminate all differences. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Wiley (2009) identified a potential trade-off in experiments using blocking. Blocking’s advantages are its ability to test secondary hypotheses, obtain “ <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 120%;">repeated measures of each experimental unit or subject <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">” ( <span style="font-family: 'Times New Roman',Times,serif; font-size: 90%;">p. 447 <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">), and reduce noise in the results. Blocking’s disadvantages are that it results in a “ <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 120%;">lower sample size. . . for testing the primary hypothesis <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">” ( <span style="font-family: 'Times New Roman',Times,serif; font-size: 90%;">p. 447 <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">) and diminishes the ability to generalize results. <span style="color: #ff0000; font-family: 'Times New Roman',Times,serif; font-size: 120%;">[These are descriptions of some of the trade offs we encounter when we conduct experiments, but I would have liked to see some explanation or examples here regarding those trade offs. For example, what do you think about some of these issues? Do you think we should try to achieve internal or external validity if we have to make a choice between the two? Do you think the advantages of Blocking outweigh the disadvantages? Why do you think some of these trade offs occur? How important are they? You could have used some peer-reviewed articles here to support or illustrate your explanation.]

<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT1] I will not deduct points for this, but we usually round these statistics, like the F value, to the nearest hundredth instead of reporting them as a whole number. See your APA manual for more details. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT2] Your MS Error is correct here, but the F values for this study are not correct. You need to divide the MS for each factor by the MS Error. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT3] Please see Comment 2. Again, the MS Error is correct, but the F values are not. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT4] This would need checked and revised based on the correct numbers <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT5] This would need checked and revised based on the correct numbers <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT6] Practice? Your calculations are correct, but you may have mis-identified your factors. Gender and Practice are the two factors here. Reaction time was the dependent variable. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT7] I see, there is just a minor wording issue. Please note that this could be confusing in a study though. This is a great example of how important it is for researchers to clearly name and identify variables (and then use those variable names consistently in their studies). <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT8] This is not a clear sentence. You are missing some words and you should check your punctuation. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT9] Check use of “affect” and “effect” here. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT10] Check word choice: “relates to” would be better here. <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT11] Check word choice. The number of participants “available for a study” is different than the number of participants “in a study” <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT12] Watch out for personification in your writing. It is not the design that “determines” interactions… <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">[TT13] This is not clear. Are there some words missing?


 * = References ||
 * * Jackson, S. L. (2012). //Research methods and statistics: A critical thinking approach// (4th ed.). Belmont, CA: Wadsworth Cengage Learning.
 * Trochim, W. M. K., & Donnelly, J. P. (2008). //The research methods knowledge base// (3rd ed.). Mason, OH: Cengage Learning.
 * Wiley, R. H. (2009). Trade-offs in the design of experiments. //Journal of Comparative Psychology, 123//(4), 447-449. doi:10.1037/a0016094 ||