In order to develop chicken pox, one must be exposed to the virus that causes chicken pox. Note, however, that not everyone who is exposed to the virus is affected. In other words, the virus is a

Craik and Watkins (1973) showed subjects lists of words (e.g. daughter oil rifle garden grain table football anchor giraffe) and told them that they would need to produce the last word begining with a given letter (e.g. G), so they had best rehearse that item. They manipulated the amount of time people had to rehearse and in a surprise recall test found:

A. Rehearsal had no impact on performance B. Rehearsal compromized performance C. Rehearsal improved performance

A reporter has been assigned to write a story about family size and intelligence. After investigating the available research, she reports that

a) the effects of birth order and family size on intelligence are based mostly on heredity. b) lower-IQ parents tend to have larger families, and these families differ from the rest of the population in variables that are correlated with intelligence. c) higher-IQ parents tend to space their children out more, thus increasing the power of birth order to affect intelligence. d) having more children leads to more stimulation, thus increasing intelligence as family size increases.