3. about 5% of the population has arachnophobia 1, which is fear of spiders. consider a random sample of 28 people and let x be the number of people in the sample who are afraid of spiders. a) carefully explain why x is a binomial random variable. b) find the probability that exactly 5 people have arachnophobia. (show calculations for b - c!) c) find the probability that at most one person has arachnophobia. d) find the probability that at least two people have arachnophobia.