Is MP3 commonly used?
Yes
What is it used for?
consumer audio streaming or storage
What is its full name?
MPEG-1 or MPEG-2 Audio Layer III
Is it used for analog audio?
No
What's the purpose of compression?
reduce the amount of data required
Should it sound different?
No
How much smaller is an MP3 file than a CD?
about 1/11 the size
Could it be smaller than that?
Yes
What would happen if it was smaller?
lower resulting quality
And if it were higher, what could happen?
higher resulting quality