According to classical test theory, s2obs = s2tru + s2err, and r11 = s2tru/s2obs. If the observed variance of a test is 50 and the error variance is 10, what is the estimated reliability of the test?
A) .20
B) .25
C) .45
D) .80

Question

Quizplus · Accepted Answer

The estimated reliability of the test is calculated using the formula r11 = s2tru/s2obs. Given s2obs = 50 and s2err = 10, we first find s2tru = s2obs - s2err = 50 - 10 = 40. Then, r11 = 40/50 = 0.80, which means the estimated reliability is .80.

According to Classical Test Theory, S2obs = S2tru + S2err