A) Study A uses a population parameter, as it is the average finish time for all 1883 finishers in the Ironman Kona race.
B) Study B does not use a population parameter, as it only includes 89 children diagnosed with cancer at one hospital.
C) Study C does not use a population parameter, as it only includes 15 patients who came in for a regular cleaning at Lakeside Family Dentistry.
D) Study D does not use a population parameter, as it only includes 3975 parents interviewed by Eugene Gilbert in the 1950s.