Pulling a sock from a drawer, replacing the sock, and pulling another sock from a drawer at random is an example of

This is an example of Independent Events.

Step-by-step explanation:

Independent events of probability are not affected by previous events.  This means that for each event, your probability is the same as before no matter the outcome of the previous events.  So, if you pull a sock from a drawer and replace it, you still have the same probability of getting that sock, or any other sock, from the drawer as you did before.  For example, if there are 10 black socks and 8 white socks, there are a total of 18 socks.  You have a 8/18 (or 4/9) chance of getting a white sock.  If you replace it, you will still have a 4/9 chance of getting a white sock again.  

pay attention in your classes and concentrate the best thing you can do to raise your test scores is to pay attention when you're supposed to be learning the material: in class!

take good notes.

do your homework.

use mnemonics and other tricks.

do practice tests.

note: the best i know.