Find a + b, 9a + 7b, |a|, and |a − b|. a = 9i − 8j + 7k, b = 7i − 9k

Kilgore trout creates a new scale to diagnose depression. however, his scale only assesses one symptom of depression while ignoring others. which of the following is his new scale most likely lacking? a) test-retest reliability b) discriminant validity c) criterion validity d) alternate-forms reliability e) content validity f) none of the above