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 EvalPre. sav and EvalPost. sav, and are saved on your computer in following file location:

C:\Documents and Settings\Evaluation\EvalData\

And suppose, finally, that you want to combine these datasets to create a new dataset, to be named EvalPrePost. sav, containing ID and X1 through X6 for all 100 participants. What SPSS syntax would you use to accomplish this?

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?