$[4$ pts$]$ If we choose the model with minimum training error, explain

why we most likely choose the most complex model $($the curve in orange$).$

Explain it using the following figure.

$[4$ pts$]$ From p$.11$&$12$ in slides, explain why minimizing $w^2$ actually has effect of making the model

simpler.

$[4$ pts$]$ You model has a high test error. You want to know whether your model has the problem of

overfitting or underfitting. How do we know this? $($Refer to p$.24$ in slides$)$ Explain the reason.

$[4$ pts$]$ Explain two data augmentation methods for text data. $(2-3$ lines$)$