Obtain a copy of the SPSS data needed for this project by opening the SPSS data file named PTSD, which is available from the college network L: drive, BUT which you may have already previously saved in your personal folder on the college network.
In your personal folder on the college network, create a Word document named PTSD (or you may use any other word processor besides Word, such as LaTeX) with the following heading:
Math 214 Project
After familiarizing yourself with the data (described in the DATA FILE 5 section of the textbook appendix), identify the two qualitative variables in the data which have more than two categories. In the first paragraph of your PTSD document, describe how you would add indicator (dummy) variables to the SPSS data file so that there is one indicator (dummy) variable corresponding to each category of each of the two qualitative variables having more than two categories. Then add these dummy variables to your PTSD SPSS data file.
Use the Analyze> Descriptive Statistics> Frequencies options in SPSS to see the range of values entered for each variable and to assess the number of missing values in the data. In the second paragraph of your PTSD document, discuss what the range of values for each of the five quantitative variables is, and how these compare with what is stated in the description in the textbook appendix. In the third paragraph of your PTSD document, discuss what the coded values for each qualitative variable are, and how these compare with what is stated in the description in the textbook appendix.
The variable Health (Overall Physical Health) will be treated as the dependent variable, and all other variables will be considered potential independent variables (i.e., predictor variables). For each of the four potential quantitative independent variables, create a scatterplot of that variable and the dependent variable Health. In the fourth paragraph of your PTSD document, discuss how each of these potential independent variables appears to be related to the dependent variable.
Submit a printed copy of your SPSS output together with your first four paragraphs by Monday April 18.
Use the Analyze> Regression> Linear options in SPSS to create a normal probability plot and a residual plot from a regression with all possible potential predictors in the model. In the fifth paragraph of your PTSD document, discuss the normality and linearity assumptions.
Use the Stepwise Regression procedure in SPSS to see which predictors are selected for the linear regression model. In the remaining paragraphs of your PTSD document, write the results of the stepwise regression using the format that we have used in previous exercises, and at the end of your document write the least squares regression equation.
Submit a printed copy of your SPSS output together with your remaining paragraphs by Wednesday April 20.
The final version of the project is due Friday April 22.