18. An educator has constructed a test for mechanical aptitude. He wants to determine how reliable the

test is over two administrations spaced by 1 month. A study is conducted in which 10 students are given

two administrations of the test, with the second administration being 1 month after the first. The data

are given in the following table.

Student Administration 1 Administration 2

1 10 10

2 12 15

3 20 17

4 25 25

5 27 32

6 35 37

7 43 40

8 40 38

9 32 30

10 47 49

a. Construct a scatter plot of the paired scores.

b. Determine the value of r.

c. Would it be fair to say that this is a reliable test?

Explain using r^2