PubH_6052_Final_Exam_.docx

PubH 6052 FINAL EXAM Please answer the following questions to the best of your ability on this document and upload it as a PDF on the 2GW online platform. Make sure that your name appears on your submission (see instructions on the Final Exam page in the Assignments section). You may use your notes, your book, or any other fixed written sources as you work on this. But please work alone on this assignment, and direct any questions or concerns to your course director or section leader. Good luck! 1. What is a codebook? Who might create one, what would she or he include in it, and what purpose or purposes would it serve? A codebook is a separate document such as a Word document or Excel spreadsheet that stores all the critical information about the data. It includes the variables, name of the variables, a brief description of the variables, questionnaire items, a sentence explaining what each variable represents, and an explanation of each numerical code. A codebook serves as a record that we can refer to if we cannot remember what was in the dataset. 2. Explain the distinction between variable labels and value labels in an electronic dataset. Variable labels describe what that variable is or what it represents. Value labels describe coded data (numbers) within a variable. For example, education levels could have the variable label “Education,” and the values labels would describe the numbers associated with a certain level of education. 3. True or False: The linear regression model cannot handle curvilinear relationships between independent and dependent variables. False 4. True or False: By convention, if we conduct a statistical hypothesis test and obtain a p-value of .3, we would reject the null hypothesis. True 5. Suppose you have two SPSS datasets. The first contains the variables ID, X1, X2, and X3 for participants 1 through 100; the second contains the variables ID, X4, X5, and X6 for the same 100 participants. Suppose that the datasets are named EvalP and EvalP, and are saved on your computer in following file location: C:Documents and SettingsEvaluationEvalData And suppose, finally, that you want to combine these datasets to create a new dataset, to be named EvalPreP, containing ID and X1 through X6 for all 100 participants. What SPSS syntax would you use to accomplish this? I would open EvalP and use Star Join to add EvalP with this syntax: STAR JOIN /SELECT t0.ID, t0.X4, t0.X5, t0.X6 /FROM * AS t0 /JOIN ‘C:Documents and SettingsEvaluationEvalDataEvalP' AS t1 ON = /OUTFILE FILE=*. 6. A research team is studying cognitive decline in old age. They collect data on 300 people between the ages of 75 and 95 years. One of the key variables is a measure of one particular aspect of cognitive functioning: Executive function (named EXFUNC in the dataset). For this study it is measured using a test that produces values ranging from 0 to 100, with higher values representing better executive function. The investigators fit a linear regression model to their data and obtain the following estimated model: EXFUNCi = 161.73 – 1.05AGEi + ei According to this model, by how many points does the typical score on the executive function scale decline between age 80 and 90? The function scale declines by 10.5 points. 7. Suppose your boss gives you a dataset and asks you to run frequencies on the variables X1 and X4, and descriptive statistics on the variables X2, X3, X5, and X6. What SPSS syntax would you use to accomplish this task? (Please present only the command(s) that generate the frequencies and descriptive statistics.) FREQUENCIES VARIABLES=X1, X4 /ORDER=ANALYSIS. DESCRIPTIVES VARIABLES=X2, X3, X5, X6 /STATISTICS=MEAN STDDEV MIN MAX. 8. Suppose your dataset has a variable, X1, that was derived from a questionnaire item with a response options ranging from Strongly Disagree (coded 1) to Strongly Agree (coded 5). Because the wording of this item runs in the opposite direction of the wording of several related items, you want to create a reverse-coded version of this variable on which Strongly Disagree will be coded 5 while Strongly Agree will be coded 1. What SPSS syntax would you use to accomplish this task? RECODE X1 (1=5) (2=4) (3=3) (4=2) (5=1) INTO X1rev. VARIABLE LABELS X1rev 'Reverse code of X1'. EXECUTE. 9. An investigator interested in regional differences in breastfeeding attitudes and practices conducts a national survey. The survey includes a multi-item instrument measuring breastfeeding attitudes. The resulting breastfeeding attitudes scale takes values ranging from 1 to 5, with higher numbers representing more favorable attitudes toward breastfeeding. This scale