Many thanks for the response. However, that wasn't my question.
In fact, I wouldn't have asked a question had I lost the mp3 file and not the wav file. My question is -- during the compression process -- when the mp3 is made -- is all information lost forever? Or, can the missing information be recovered if I load the mp3 into the software and save it as a wav file?
In other words, I don't know how the compression process works.
You may want to know why I just don't make another wav file since I have the original audio file. Well, I tried that yesterday, and the new wav file has some "static pops" on it that somehow I managed to eliminate when I made the previous (lost) wav and mp3 files. I know the pops are from amplification, but while normalizing the file got rid of them the first time, normalizing did not get rid of all of them yesterday.