1. The following table contains information on a population of N=6,732 individuals who are classified as having or not having prevalent Parkinson's disease (PD). Each individual is also classified in terms of having a family history of PD. In this analysis, family history is defined as a first degree relative (parent or sibling) with diagnosed PD before age 65. Use these data to answer the questions below the table.

	Prevalent PD	Free of PD	Total
Family history of PD	491	368	859
No family history of PD	152	5,721	5,873
Total	643	6,089	6,732

a. What is the probability that a randomly-selected person from this population will have a family history of PD and have prevalent PD?

b. What is the probability that a randomly-selected person from this population will have a family history of PD?

c. For someone with a family history of PD, what is the probability that they will have prevalent PD?

d. Are family history of PD and prevalent PD independent? Explain.