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 fi rst. The data are given in the following table.

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 r2.
education

Student Administration 1 Administration 2 10 1 10 22 1 15 30 2 17 45 2 25 57 2 32 65 3 37 7 3 40 10 80 92 47 + 38 3 30 49