About ___% of teenage boys and girls identify themselves as gay or lesbian

One problem with using archival data (e.g., existing records of disturbances) to demonstrate that exposure to uncomfortable levels of heat causes people to behave aggressively is that

A) more people might simply be outside on a warm day than on a cold day. B) by definition, people who participate in disturbances are not a random sample. C) it is difficult to access such records. D) the records focus on the past 200 years. E) such disturbances do not involve the kind of aggression of interest to social psychologists.

What percentage of babies did Thomas and Chess find met their definition of "easy" babies?

a. 20% b. 40% c. 60% d. 80%