CAS Exam MAS-I Fall 2019, Question 39
Study guide: Exam MAS-I
An actuary has a dataset with one dependent variable, Y, and five independent variables (X_1, X_2, X_3, X_4, X_5). She is trying to determine which subset of the predictors best fits the data, and is using a Forward Stepwise Selection procedure with no stopping rule. Below is a subset of the potential models:
| Model | Dependent variable | RSS | Independent variable | p-value |
|---|---|---|---|---|
| 1 | Y | 9,823 | X_1 |
0.0430 |
X_2 |
0.0096 | |||
| 2 | Y | 7,070 | X_1 |
0.0464 |
X_2 |
0.0183 | |||
X_3 |
0.0456 | |||
| 3 | Y | 6,678 | X_1 |
0.0412 |
X_2 |
0.0138 | |||
X_4 |
0.0254 | |||
| 4 | Y | 4,800 | X_1 |
0.0444 |
X_2 |
0.0548 | |||
X_5 |
0.0254 | |||
| 5 | Y | 3,475 | X_1 |
0.0333 |
X_2 |
0.0214 | |||
X_3 |
0.0098 | |||
X_4 |
0.0274 | |||
X_5 |
0.0076 |
The procedure just selected Model 1 as the new candidate model.
Determine which of the following independent variable(s) will be added to the model in the next iteration of this procedure.
- A) No variables will be added
- B)
X_3only - C)
X_4only - D)
X_5only - E)
X_3,X_4andX_5
Answer this question and see the worked solution