Why is it logical to use the set of features that result in the smallest average root mean squared error when performing cross-validation?

Consider a byte-addressable computer with 16mb of main memory, a cache capable of storing a total of 64kb of data and block size of 32 bytes. (a) how many bits in the memory address? (b) how many blocks are in the cache? (c) specify the format of the memory address, including names and sizes, when the cache is: 1. direct-mapped 2. 4-way set associative 3. fully associative

In the context of the box model, what is the difference between a margin and a padding? a. a padding lies outside a box border, while a margin lies inside it. b. a padding lies inside a box border, while a margin lies outside it. c. a padding can be adjusted independently, while a margin depends on the size of its box. d. a padding depends on the size of its box, while a margin can be adjusted independently.

Worth 50 points answer them bc i am not sure if i am wrong