Which of the following statements are incorrect?

A.Recall bias is a form of measurement bias that can occur in case-control and cross-sectional studies because of differential recall about past exposures between those who have the disease and those who do not have the disease.

B.Selection bias is systematic error that results from the way in which the subjects are selected or retained in a study

C.Selection bias is an error that can occur when the characteristics of the subjects selected for a study differ systematically from those in the target population.

D.Recall bias is a form of selection bias that can occur in case-control and cross-sectional studies because of differential recall about past exposures between those who have the disease and those who do not have the disease

1. The null hypothesis states that an exposure/disease association exists beyond what might be expected from random variation alone.

True

False