This group is quite heterogeneous some are very rich while some are very poor.

Solution (By Examveda Team)

Contradictory : mutually opposed or inconsistent.
Uniform : remaining the same in all cases and at all times; unchanging in form or character.
Confusing : bewildering or perplexing.
Varied : incorporating a number of different types or elements; showing variation or variety.
Heterogeneous : diverse in character or content.

Synonym of Heterogeneous is Varied