Researchers have found that a high level of _____, one of the Big Five personality dimensions, may be a risk factor related to mood disorders

At 6 months of age, American infants sleep about 14 hours a day, whereas infants who are the same age in Kenya sleep about 12 hours a day, and infants in the Netherlands sleep about 16 hours a day. This variation is best described by ____

a. reflexive responses b. cultural practice c. innate preprogramming d. biological influence

Dr. Salahma conducts a study on teenagers and product preference. In his study, he begins with a diverse sample of 13-19 year olds

However, after the first few trials of the experiment many of the 15 year old males in the experiment stop responding to the questions and choose not to participate in a follow up session. Dr. Salahma needs to be concerned about a. random assignment. c. cohort effects. b. selective attention. d. selective dropout.