Professor Washington is conducting research into the causes of test anxiety. In order to determine their level of anxiety, she has her participants wear a device that tracks their heart rate variability while they are taking an exam (lower levels of heart rate variability are indicative of higher levels of anxiety). In this research, what is heart rate variability

Dr. robbins wants to know if there are different opinions regarding the value of public school education between native americans who have at least one relative who attended indian boarding school and native americans who have no family experience with indian boarding school. dr. robbins contacts 35 native american participants in each group. he wants each group to include younger as well as older adults, and a mix of male and female participants. he asks each person to complete a survey about their attitudes toward public education. the design of this study is: