Jan and Peter have been romantically and sexually involved for six months. Their sexual orientation would best be characterized as

Compared to breastfed babies, bottle-fed infants

A) are leaner. B) have more respiratory illnesses. C) have far fewer allergic reactions. D) have lower blood cholesterol levels in adulthood.

Why is random assignment important in an experiment?

a. It assures that all participants take part in all conditions of a study. b. It allows researchers to rule out individual differences as an alternative explanation. c. It ensures that all participants see the same manipulation of the independent variable. d. It is an index of the probability that experimental results occurred by chance.