It is conjectured that an impurity exists in 30% of all drinking
wells in a certain
rural community. In order to gain some insight on this problem,
it is determined that some tests
should be made. It is too expensive to test all of the many
wells in the area, so 10 were randomly
selected for testing.
a. What is the probability that three wells from the
sample are impure? Round
your answer to the nearest hundredths.
b. What is the probability that three wells from the
sample are pure? Round
your answer to the nearest hundredths.
c. What is the expected value of impure wells?