Which of these is an example of a longitudinal study?
a. The depth perception of infants is measured once a month for 6 months in a row, starting at six months.
b. In the same month, researchers compare the reaction time of 20 sixth graders and 20 first graders
c. The memory of one group of 50 -year-old adults is measured and then 20 years later compared to a different group of 70 -year-olds.
d. A psychologist develops a case study of a woman who is 102 by interviewing her twice a week for 12 weeks.
e. Researchers compare curiosity ratings of a group of toddlers with that same group's SAT scores 15 years later.