1. What is selection bias? a) Study participants are selected to the study in a bad way b) The same as confounding c) Cases are selected to a cohort study in a bad way d) None of the above

2. What is the Median? a) Same as the mean value b) The middle observation in a ranked data set c) A measure of variation d) None of the above

3. What is the mean of the following serie? 1,1,3,5,6 a) 3.1 b) 3.2 c) 16 d) None of the above

4. What is true for a confounder? It is only associated with the outcome It is only associated with the exposure It is the same as colinearity None of the above

5. What is variance It is the same as causality A point estimate A measure of how far data are spread out None of the above