According to classical test theory, if the observed variance of a test is 50 and the true variance is 40, what is the estimated reliability of the test?

Answer
a.
0.40
b.
0.50
c.
0.80
d.
0.90

The ratio of true score variance to the observed score variance: 40/50 = 0.80

0.80

The ABC Self-Concept Inventory has a split-half reliability coefficient of 0.90, and the XYZ Self-Concept Inventory has a Spearman-Brown reliability coefficient of 0.90. If all other factors are equal, which instrument would you choose to use?

Either one

0.40

90

.80