Exam 1

1. Metainformation

   Tag	Value
   file	Reliability_eur-reliability-215-en_eur-reliability-215-en
   name	eur-reliability-215-en
   section	Reliability/Analysis/Cronbach's alpha
   type	string
   solution	""
   Type	Calculate, Interpreting output
   Program	Calculator
   Language	English
   Level	Statistical Literacy

   Question

   Exams aim at measuring a person’s true score. The accuracy of this measurement of the true score will likely be lower if the reliability of the test is too low. One way to theoretically compensate for this lower accuracy is by calculating the adjusted true score: $X_{est} = x̄ + R_{xx}(X_o-x̄)$

   Students doing the exam on psychometrics need a 6.0 the pass at the exam. One student has a 6.0. The average score is 5.8 and the reliability of the exam is .31. Do you advise this student to complain about the reliability of the exam? Explain why.

   
   

   Solution

   The adjusted true score (estimated true score) for a student having an observed score of 6 is: $X_{adj} = 5.8 + .31(6.0 - 5.8)$ $X_{adj} = 5.8 + .062 = 5.862 = 5.9$

   The estimated score is 5.9, which is below the criterion. So in this case the student can better be happy with the lower reliability