I want you to take a look at this poll by Suffolk of the race for congressional district 2 in Rhode Island:
RHODE ISLAND 02: Republican Alan Fung vs Democrat Seth Maganizer
Overall: 45/39
LIKELY VOTERS: 46/38 (Fung +8)
Male: 56/32
Female: 34/45
Dem: 12/77
GOP: 89/5
Indie: 58/20 (Fung +38)
18-34: 43/33
White: 45/40
Black: 26/57
Hispanic: 51/30
06/19-22 / 423 LV / Suffolk / D40/R14/I46
Granted, Rhode Island is a tiny state with only two congressional districts, but each of those districts is home to roughly 700,000 citizens, the same as every other district in the United States. So, this one is as representative as any other.