The collective nouns are:a crowd of spectatorsan audience of spectators.
A group of spectators are called an audience.
An audience or a crowd.
All of the people attending a football game are a group of spectators.
No. It's just the plural form of a singular noun. If you said 'a group of spectators' the word group would be a collective noun.
Male spectators in the 15/95 age group.