How does our text define stereotyping?

Our readings in Chapter 11 discuss stereotyping.  How does our text define stereotyping? Are stereotypes always inaccurate? What are some ways stereotypes might be useful?  How might we make our stereotypes more efficient?  How is this related to the perceived outgroup homogeneity effect?

reference: Kenrick. Social Psychology: Goals in Interaction. 6th edition Pearson Custom (REVEL access)