Part II: Short answer questions. 9.
The manufacturer of exercise machines for fitness centers has designed two new elliptical
machines that are meant to increase cardiovascular
fitness. The two machines are being
tested on 30 volunteers at a fitness center near the company's headquarters. The
volunteers are randomly assigned to one of the machines and use it daily for two months.
A measure of cardiovascular fitness
is administered at the start of the experiment and
again at the end. The table below contains the differences in the two scores (After-
Before) for the two machines.
Machine A
6,1
9, 7, 4, 1, 1
8, 7, 6, 3, 2,0
5, 4
5
4
3
2
1
0
Machine B
3, 5, 9
2, 5, 7
2, 4, 8, 9
1, 5, 9
0
2
(a) What is the center of the two distributions? Write a sentence comparing the two centers.
(b) How would you describe the shape of the two distributions? Write a sentence comparing
the shape of the distributions.
(c) What is the spread of the two distributions? Write a sentence comparing the spread of
the distributions.