How is the global test score supposed to be computed based on the individual scores in the Wechsler Nonverbal Scale of Ability?
Let's say the sub-test scores are A, B, C, and D.
- how do we obtain the global score? is it age dependent?
- I understand that the standard deviation on the total score is 15. Is this correct?
- how is the confidence interval computed? is it symmetric around the "measured" value?