"People sometimes describe themselves differently than they are described by others (a discrepancy between S data and I data), and they sometimes describe themselves differently from how they act (a discrepancy between S data and B data). Why might this happen? If your sociability data differed, which would you tend to believe and why?"

Step-by-step explanation:

From the information given,

S DATA = The way people describe themselves

I DATA = The way others describe these people

B DATA = The way these people act, in reality

Why might this happen?

This happens because every human has their own point of view; we all see and speak differently of ourselves and of others. In between, the true character or behavior exists!

If your sociability data differed, which would you tend to believe and why?

If my sociability data differed, as described in the question - where S DATA differs from I DATA and S DATA differs from B DATA - I would believe the S DATA because B DATA that is negative (unpleasant) is sometimes influenced by unpleasant situations, feelings, and unpleasant actions from other people.