As the heart beats, blood pressure increases and decreases. This happens cyclically at the rate of the
person's heart beat. A doctor is monitoring the blood
pressure of a patient whose heart rate is 70 beats per
minute. The maximum blood pressure over the course of
a 10-minute period is 120 mm/Hg and the minimum is 60
mm/Hg.
Find a sine function that models the person’s blood pressure as a function of time (in minutes).

Jeffery conducted a survey in his school and found that 30 of the 50 eighth grade students' favorite subject is mathematics. based on the results, jeffery concluded that out of the 200 students in his school, 120 students' favorite subject is mathematics. select the statement that is true about jeffery's conclusion. a. jeffery's conclusion is not valid because the sample was biased since only 200 students were surveyed. b. jeffery's conclusion is valid because the sample was random since all of the students were eighth grade students. c. jeffery's conclusion is valid because the sample was random. d. jeffery's conclusion is not valid because the sample was biased since all of the students were eighth grade students.