The rival software companies TechCo and TypePlus each released typing software designed to help college students improve typing accuracy. Both companies advertise the effectiveness of the software by stating that after 4 months of practice with their respective software, people will commit fewer typing errors (e.g., misspelled words). Dr. Franks, a Computer Science professor, wanted to know which software was more effective, so he conducted a study to test them. Dr. Franks recruited undergraduate first-year students from his Computer Science classes to participate in his typing study. He randomly assigned participants to practice typing using the TechCo software or the TypePlus software. First, he obtained a baseline of their typing abilities by giving participants a typing pretest. Then, participants started practicing using the software in Dr. Frank's lab and after 4 months of practice he administered another typing test (i.e., posttest). These tests consisted of typing, as accurately as possible, a passage from an audiobook which participants heard through headphones (different passages were used for each test). The results of the study are presented in the table below, which displays the number of typing errors made by the participants based on the software they were assigned, and a given test. Use that data to answer the questions that follow. Round to three decimal places in your calculations. Provide directional hypotheses where appropriate. Please number all of your answers in the answer box below and on your worksheet. The t-table and formulas are located at the bottom of the exam. 1. Conduct the appropriate test and determine which typing software was the most effective in helping students improve their typing skills. Use an alpha of .05 and a two-tailed test. (Total 10 points) A. State all relevant hypotheses needed for the statistical test. (2 points) B. Report the results and all relevant statistics needed to understand the results. (4 points) C. Based on the results, which company has the more effective typing software? (4 points) 2. Conduct the appropriate tests to determine if students in each group improved their typing skills. Use an alpha of .05 and two-tailed tests. (Total 15 points) A. State all relevant hypotheses needed for the statistical tests. (2 points) B. Report the results and all relevant statistics needed to understand the results. (6 points) C. Based on the results, which group improved the most? Explain. (7 points) 3. Dr. Frank was a little worried the baseline data for the TechCo group was a little low. He wondered if, by chance, the participants assigned to this group were already good typists. So, he obtained reliable data showing that, on average, college students nationwide (i.e., the population) make 7 typing errors (on similar typing tests). (Total 10 points) A. Conduct the appropriate test to determine if the baseline data for the TechCo group differs from all college students. Use a two-tailed test and alpha of .05. B. State all relevant hypotheses needed for the statistical test. (2 points) C. State and interpret all relevant results and statistics. (4 points) D. What would be the concluded from these results? (4 points) 4. Based on the results of the test for Question #3, Dr. Franks concluded that the baseline scores for both groups did not differ from the population. Explain why he is or isn't justified in making this conclusion. Be specific. (5 points) 5. Dr. Franks's study is not perfect. Name two limitations that could be present in his study. Describe how they potentially affect the results. And what can be done to address these limitations? Be specific. (5 points) 6. Describe a specific alternate design Dr. Franks can use to assess the same research issue in the study described above. And, how would that alternate design be analyzed? Be specific. (hint: your answers should include, but not be limited to: type of design, variables, type of test analysis) (5 points) Group Participant Pretest Posttest Group Participant Pretest Posttest TechCo #1 6 4 TypePlus #6 6 5 #2 6 2 #7 5 4 #3 5 2 #8 5 6 #4 8 3 #9 6 5 #5 7 4 #10 6 4 m = = 6.4 m = 3 m = 5.6 m = 4.8 sd=1.14 sd = 1.0 sd=0.55 sd = 0.84 Formulas t = m- Sm = Sm S d = m- S m1 - m2 [(n 1)s + (n 1)s]| |n + n n + n - 2 1)]|| nn2 d = m1 - 2 m2 t = nD - (D) n-1