A property-price model is trained on four homes. The raw features are:
| home | bedrooms | age (years) |
|---|---|---|
| A | 2 | 10 |
| B | 3 | 5 |
| C | 3 | 20 |
| D | 4 | 8 |
Before fitting, a column of ones is prepended to this table so the model can learn an intercept. Call the resulting design matrix , with its columns ordered .
What is the shape of , and what is the value of its diagonal entry belonging to the bedrooms column?
Once you get it right, the reasoning behind the answer shows up here.
Select all that apply.