John Always Gets Nervous During Exams,which Results in Him Consistently

Multiple Choice

John always gets nervous during exams,which results in him consistently receiving 20 fewer points on formal exams than on assignments done under identical conditions at home.The difference between his actual test score and true score (that is,the score he would have received normally) can be considered what sort of error?

A) Random
B) Systematic
C) Unpredictable
D) Instrumentation
E) None of the above