Why do MOST PEOPLE tend to SING BETTER in HUGE-MASS, than to SING ALONE?

Question:

Why do MOST PEOPLE tend to SING BETTER in HUGE-MASS, than to SING ALONE?

For example, if we gather enough people to fill the MADISON SQUARE GARDEN or the SUPERDOME, and let everyone sing the Star Spangled Banner altogether?? we will hear a kinda nice melody of this song??

BUT?? if we separate those people one by one, and ask only one person per turn to sing?? we??ll get lots of awful and dreadful singer there (I guarantee that we??ll hear many sing off-key or out of tune! Ever watch American Idol show? If you do, you??ll understand what I mean here) Why? What makes most (NOT ALL!!) people sing better collectively than individually?

PS: Few people are exceptional of course! They are the talented one, and they surely can sing better, above average. But my point here is the majority: the below average one.

Best Answer - Chosen by Asker:

Good singers are the reason the music sounds better. First of all, the bad singers tend to mouth the words or sing relatively quietly, although there are exceptions, but the good singers always sing there heart out and that is what you hear overall.

Finally, there are people out there who probably have decent voices if they weren't tone deaf...if good experienced singers are carrying the song, they have an easier time following.

Also, the combination of voices creates a different sound.