Sociology: Social Media With as much attention as Twitter gets in the news, you might be surprised to learn that only about 10% of people in America use Twitter. In a group with 20 people (assume that it is a random sample of people in America), what is the probability that

(a) at least one of them uses Twitter?

(b) more than two of them use Twitter?

(c) none of them use Twitter?

(d) at least 18 of them do not use Twitter?

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