statistics
posted by jerry .
According to the Smart magazine, 70% of smokers started smoking before the age of 18. Suppose 10 smokers are randomly selected and the number of smokers who started to smoke before the age of 18 is recorded.
a) explain why this is binomial experiment.
b) find the probability that exactly 7 of them started smoking before the age of 18.
c) find the probability that at least 7 of them started smoking before the age of 18.
d) find the probability that fewer than 4 of them started smoking before the age of 18.
e) find the probability that between 8 and 10 (inclusive) of them started smoking before the age of 18.

b)