Assignment 8

Objective

Predict cheaters using the Affairs data from the AER package, using the classification algorithm from the rpart package.

Data Prep

Created a new binary variable cheater by classifying observations with 0 affairs as 0, and with one or more affairs as 1.
Split the data (601 observations), into training and validation datasets (70%/30% , 425/176)

The Tree

Two Interpretations from the Tree

The most likely cheaters:

been married more that 2.8 years
Not very religious (religiousness < 4)
Educated (education > = 17 years)
Rates their marriage not so well (rating < 4)

Unlikely cheater

Newlywed (years married < 2.8 years)

Variable Importance

Interesting how gender is perceived by many as a predictor for cheating. However, the data shows that it is not a good predictor.

Model Accuracy

Using the validation data, it is observed that the model is able to:

Predict correctly 27% of the cheaters
Misclassify faithful people as cheaters 8.6% of the time

## 
##  
##    Cell Contents
## |-------------------------|
## |                       N |
## | Chi-square contribution |
## |           N / Row Total |
## |           N / Col Total |
## |         N / Table Total |
## |-------------------------|
## 
##  
## Total Observations in Table:  4445 
## 
##  
##                  | val$left 
## val$predicted_rf |         0 |         1 | Row Total | 
## -----------------|-----------|-----------|-----------|
##                0 |      3393 |        29 |      3422 | 
##                  |   228.713 |   746.005 |           | 
##                  |     0.992 |     0.008 |     0.770 | 
##                  |     0.997 |     0.028 |           | 
##                  |     0.763 |     0.007 |           | 
## -----------------|-----------|-----------|-----------|
##                1 |         9 |      1014 |      1023 | 
##                  |   765.061 |  2495.434 |           | 
##                  |     0.009 |     0.991 |     0.230 | 
##                  |     0.003 |     0.972 |           | 
##                  |     0.002 |     0.228 |           | 
## -----------------|-----------|-----------|-----------|
##     Column Total |      3402 |      1043 |      4445 | 
##                  |     0.765 |     0.235 |           | 
## -----------------|-----------|-----------|-----------|
## 
##