The standard error of measurement of a particular test of anxiety is 8.A student earns a score of 60.What is the confidence interval for this test score at the 95% level?
A) 52-68
B) 40-68
C) 44-76
D) 36-84

Question

Quizplus · Accepted Answer

To calculate the confidence interval, we use the following formula:
CI = X ± (Z * SEM)
Where,
CI = Confidence Interval
X = Test Score earned by student (i.e., 60)
Z = Z-value corresponding to the desired level of confidence (i.e., 1.96 for 95%)
SEM = Standard Error of Measurement (i.e., 8)

Plugging in the values, we get,
CI = 60 ± (1.96 * 8)
CI = 60 ± 15.68
CI = (60 - 15.68) to (60 + 15.68)
CI = 44.32 to 75.68

Therefore, the confidence interval for the test score earned by the student at the 95% level is 44-76 (Option C).

The Standard Error of Measurement of a Particular Test of Anxiety