Name:_____________________________ HP340: Statistical Methods, Fall 2016 Due Date: Nov 2, 2016 Homework #6 Instructions: Clearly circle the letter of the best answer for multiple-choice questions and show your work when calculations are required. Where necessary, please explain your reasoning for the approach you used. 1. Researchers at the Keck School of Medicine are designing a laboratory-based experiment to examine the effects of a new drug to treat anxiety. They have enough research funding to collect data on a maximum of 20 participants. They decide to use a paired (or within-subjects) design as opposed to a between-subjects design. What do you think the rationale for their choice is? (choose all that apply) (2 points) a. b. c. d. 2. A paired (or within-subjects) design will have increased power A paired (or within-subjects) design will have decreased power A paired (or within-subjects) design will have a greater pooled s2 A paired (or within-subjects) design will have a smaller pooled s2 In the above example, the researchers change their minds and decide to use a onefactor between-subjects design. In this study, they will collect data from participants who meet criteria for an anxiety disorder. These participants will be randomly assigned to one of two \"drug condition\" groups: a) one group that receives the active medication; and b) one group that receives placebo (a non-active pill). They will then measure selfreported anxiety using a validated questionnaire following administration of either the active medication or a placebo. What is the factor in this example? (2 points) a. b. c. d. participants who meet criteria for an anxiety disorder self-reported anxiety drug condition None of the above 3. Which of the following will increase the power of an independent-samples t test? (choose all that apply) (2 points) a. decrease the difference between sample means b. increase the difference between sample means c. decrease the value of the standard error of the sample means d. increase the value of the standard error of the sample means 4. A group of researchers at UCLA conducted a study in which they compared cocaine users to non-using controls on several measures of cognitive performance. The cocaine users performed significantly worse than the controls on most of the cognitive performance measures. On closer examination, the researchers noticed that the cocaine users had significantly lower levels of education, and levels of education are associated with cognitive performance. In this example, the researchers used a ________________ design that had a confounder: ______________. (2 points) a. between-subjects; level of education b. within-subjects; level of education c. between-subjects; cocaine use d. within-subjects; cocaine use 5. Given the following information calculate the tobs for testing the difference between Time Point 1 and Time Point 2 in a single sample. Using a two-tailed test at =.05, what do you conclude? (Write an informative and complete conclusion statement) (8 points) N=61; s 2D = 285.49; Time Point 1 X = 80.26; Time Point 2 X = 84.72 The SPSS file posted on BlackBoard (HW6.data.sav) contains midterm and final exam scores for a group of students taking an Intro to Statistics course. Use this data file to answer Questions 6 and 7. For both of these questions, be sure to provide the null and alternative hypothesis, copy-and-paste the relevant SPSS output used to answer the question, and write an informative and complete conclusion statement. Use =.05 for both questions. 6. Did the women do better or worse on the final exam compared to the men? (15 points) 7. Did the students do better on the final exam compared to the midterm? (15 points) \f\f\f\f\f$FL2@(#) IBM SPSS STATISTICS 64-bit Macintosh 22.0.0.0 ################d#########Y@26 Oct 1611:34:46 ###########################STUDENTI########################GENDER ########################MIDTERM ########################FINALEXA#################Female ######?#Male ######################################################################### ############ ####################################################### #######C###STUDENTI=StudentID GENDER=Gender MIDTERM=Midterm FINALEXA=FinalExam########################d###################V###StudentID: $@Role('0' )/Gender:$@Role('0' )/Midterm:$@Role('0' )/FinalExam:$@Role('0' ) #######edfdgdhdidjdkdldmdndodpdqdrdsdtdudvd wdxdydzd{d| d}d~ddd}ddddddddddddddd~ dddddd}de~eeeeeeeeeeee eeeeeeeeeeee~eeeeeeee eeeeeeeeeeeeeeeee