A swim instructor would like to test the effect of a new swim technique versus the standard technique for a group of 25 competit
ive swimmers. The swim instructor divides the students by class (junior or senior), and then randomly allocates half of the 14 juniors and 5 of the 11 seniors to receive instruction on the new technique.
During swim practice, the instructor times the juniors as they race against each other to see if those who learned the new technique outperform their peers. The instructor does the same for the seniors.
At the end of practice, the instructor compares the average swim time for both juniors and seniors among those who did and did not use the new technique.
A) The instructor should place the 25 student names on slips of paper and place them in a hat. Twelve of the slips should be drawn out and those students should receive the instruction on the new technique.
B) The instructor should place the names of the 14 juniors on slips of paper and place them in one hat. The 11 seniors’ names should be placed on slips of paper and placed into a separate hat. The instructor should randomly select 7 juniors and 5 seniors to receive instruction on the new technique.
C) For each student, the instructor should flip a coin. If the coin lands on heads, the student will receive instruction on the new technique. If the coin lands on tails, the student will not receive instruction on the new technique.
D) The students should line up alphabetically and count off by 2s. Every student who gets a 1 will receive instruction on the new technique. Every student who gets a 2 will not receive instruction on the new technique.
Since the measure of an exterior angle is equal to the sum of any two angles in a triangle, the equation would be 4x-18=2x+6+36. Solve this, and we get x=30.
