Trulia gets their information from public records and selects the sold properties in the neighborhood that they feel are most comparable. Obviously, Trulia is not based in the area so have no idea of the condition of these properties nor which neighborhoods are more desirable than others.
Here is Trulia's contact number if you wish to discuss it with them: 888-466-3501. The phone lines are available M-F from 7:00 am- 4:00 pm PST as they are based in California.
Hope this is helpful!
Prudential Connecticut Realty