Which of the following research situations would be most likely to use an independent-measures design?
a) examine the development of vocabulary as a group of children mature from age 2 to age 3
b) examine the long-term effectiveness of a stop-smoking treatment by interviewing subjects 2 months and 7 months after the treatment ends
c) compare the mathematics skills for 9th grade boys versus 9th grade girls*
d) compare the blood-pressure readings before medication and after medication for a group a patients with high blood pressure