In a matrix for a factorial design, the row means and column means represent the effects of:

To increase his sample size, Denzell asks parents of children in his study to nominate friends

that might also like to be in the study. This sampling method is known as: A) a sampling frame. B) simple random sampling. C) probability sampling. D) snowball or chain sampling.

Which of the following is generally true for people in their old age?

a. The frequency of intense negative emotions is highest at the age of 65. b. As people get older, most become better able to regulate negative feelings and emphasize the positive. c. People who have challenging occupations lose their cognitive abilities. d. Cognitive enrichment can prevent most cases of serious cognitive decline and dementia.