9. Suppose your team has been analyzing data from an impact evaluation that used a one-group pretest-posttest design. Among the 50 participants in this evaluation study, individuals were classified as either sick or not sick both before and after the intervention. The pre-intervention measure appears in the dataset as a variable named SICKPRE, taking values 0 for not sick and 1 for sick. The post-intervention measure uses the same coding scheme and is named SICKPOST. A member of your team has used McNemar's test to see whether the proportion of participants who were sick declined significantly over the course of the intervention, and you have been presented with the output appearing in Appendix 3. Looking at this output, did the proportion classified as sick increase or decrease over the course of the intervention, and was this change statistically significant?

10. Explain the distinction between variable labels and value labels in an electronic dataset.

11. Suppose your dataset has a variable, X1, that was derived from a multiple-choice question with response options coded 1, 2, 3, 4, and 5. And suppose that the response option coded 4 is the correct response. What SPSS syntax would you use to derived a right-wrong recoded variable, named X1rw, that takes the value 1 for respondents who answered the question correctly and 0 for those who answered incorrectly?

12. True or False: A linear regression model with a single dummy variable predicting a continuous dependent variable is equivalent to an equal variances independent samples t-test.

13. What is a codebook? Who might create one, what would she or he include in it, and what purpose or purposes would it serve?

14. 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, executive function 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 where age is measured in years:

EXFUNC_i = 161.73 - 2.08AGE_i + e_i

According to this model, by how many points does the typical score on the executive function scale decline between age 80 and 90?

15. Suppose you have a dataset that includes the variable AnemCat as described in question 8, and bar graph that shows how many people fall into the four categories: no anemia, mild anemia, moderate anemia, and severe anemia. Write out the complete SPSS syntax that you would use to obtain that bar chart.

16. True or False: A cross-tabulation is a useful way of examining how two continuous variables are related.

17. Suppose you are conducting an impact evaluation using a posttest-only design with three groups: a control group, a group receiving treatment A, and a group receiving treatment B. The dependent variable is continuous, and sample is n=1,023, with participants approximately evenly divided between the three groups. What statistical test would be most appropriate for testing the null hypothesis of no difference between the three groups in the mean level of the outcome variable?

18. Suppose that you a part of a team that has been analyzing data from an impact evaluation that a one-group pretest-posttest design. Measures of social support were obtained before and after the intervention using the same instrument. They are continuous. The pre-intervention social support variable appears in the dataset as SSPRE, and the post-intervention appears as SSPOST. A paired t-test was conducted and you have been presented with the output appearing in Appendix 4. How would you quantify the estimated effect of the intervention in terms of a mean difference, and do the statistical tests provide support for the effectiveness of this intervention?

19. Suppose you want to conduct McNemar's test to see if the prevalence of anemia changed significantly between baseline and follow-up in a single group of study participants (n=112) who were offered iron folic acid supplements between the two time points. The variables AnemiaPre and AnemiaPost are both 0-or-1 indicators of having anemia. Write out the complete SPSS syntax that you would use to obtain McNamar's test.