Suppose a certain opthalmic trait is associated with eye color. 300 randomly selected individuals are studied with results
as follows:
EYE COLOR
TRAIT | Blue | Brown | Other | Total
____________________________________
Yes | 70 | 30 | 20 | 120
____________________________________
No | 20 | 110 | 50 | 180
____________________________________
Total | 90 | 140 | 70 | 300
A. What is the probability that a person has blue eyes?
B. What would you expect to be the value P(having the trait and blue eyes) if eye color and trait status were independent?
C. Which of the following expressions describes the relation- ship between the events A = a person has brown eyes and
B = a person has blue eyes? (circle the correct answer)
i. independent ii. exhaustive
iii. simple iv. mutually exclusive