4. The tables below show the correct and observed (imperfect) classification of exposure and disease in a cohort study.
CORRECT CLASSIFICATION
D+ D-
E+ 25 10
E- 45 90
OBSERVED CLASSIFICATION
D+ D-
E+ 34 10
E- 36 90
Calculate the appropriate measure of effect, describe the type of misclassification (if any) and the resulting bias (if any).