$3.(10$ points$)($a$)$ Decide whether the following statement is true or false:

Scaling numerical variables can sometimes improve the error of predictions of linear regression models.

$($b$)$ In this class we have learned about several machine learning algorithms. These

include the following: decision trees, bagging, random forests, nearest neighbor,

linear regression, k$-$means clustering, hierarchical clustering.

Of these $7$ algorithms, is any a generalization of any other, or are they all

essentially different? Say which of these options is correct, and if one is a

generalization of another give a specific example.