2. In a cohort study with no loss to follow-up, disease status was misclassified as follows:

Study Population without Misclassification

Exposed and Ill: 500

Exposed and healthy: 3000

Unexposed and ill: 500

Unexposed and healthy 3250

Study pop with misclassification:

Exposed and Ill: 650

Exposed and healthy: 2850

Unexposed and ill: 200

Unexposed and healthy 3300

a. What is the most appropriate relative measure of association to use in this study? For a cohort study the most appropriate relative measure of association to use it

b. Comparing the study population with and without misclassification using this measure of association, is there evidence of information bias?

With:

Without:

Evidence of information bias:

c. If there is evidence of information bias, is it differential or non- differential? Explain why by comparing the errors in misclassification of disease between the exposed and unexposed.

Exposed:

Unexposed:

Differential or nondifferential:

d. If there is information bias, is it towards or away from the null? Why?

Informational Bias is toward or away from null because.