Suppose that Jane makes a score of 60 on a test having a standard deviation of 5 and a reliability coefficient of .85. Between what two values can we be 95% confidant that Jane's true score on the test falls?
A) 59-61
B) 57-63
C) 56-64
D) 55-65

Question

Quizplus · Accepted Answer

The standard error of measurement (SEM) is calculated using the formula SEM = SD * sqrt(1 - reliability). Here, SEM = 5 * sqrt(1 - 0.85) = 5 * sqrt(0.15) ≈ 1.94. For a 95% confidence interval, we use approximately 2 SEMs, so the interval is 60 ± 2(1.94), which is approximately 56 to 64.

Suppose That Jane Makes a Score of 60 on a Test