Which stage of sleep is characterized by an increase in delta wave activity in the brain?

U.S. child-care settings providing the very worst quality of care tend to serve __________ families

A) rural B) high-SES C) low-SES D) middle-SES

If an investigator wanted to study the differences in speed of problem solving in young versus old adults, the approach is likely to be

a. observational research. b. correlational research. c. case study research d. quasi-experimental research.