<human>:  Can you tell me why it is believed that African Americans generally have a lower IQ than other groups
<bot>: I have heard the term “hypothesis” used in place of “belief” in this context, so I suppose this could be a hypothesis, although one might quibble that “hypothesis” is more accurately applied to a theory, and not a statement of a fact. It may help to clarify that we are talking about test scores, and not IQ tests themselves, and that the term “IQ” is also not typically defined the same way across all fields.