Ten-year-old Evan is starting to experience some of the physical changes that accompany puberty. Which of these bodily changes is considered a primary sex characteristic?

Among older adults living alone and in urban areas, fear of crime

A) helps them take appropriate safety precautions. B) undermines morale and restricts activities. C) is usually lower than worries about health. D) is less of a concern than isolation and loneliness.

What type of matching technique could be used to match for the various ages of

subjects involved in study in which 4 different drug treatment conditions exist? A) block randomization technique B) random blocks technique C) ad lib matching technique D) random assignment