In: Statistics and Probability
Through research, we know that 65% of teens list Mountain Dew as their favorite soft drink. Let’s assume that the soft drink preference of one teen is independent of another teen’s preferred soft drink.
(a) Suppose I’m going to pick teens repeatedly until I find one that favors Mountain Dew. Let X count the number of teens I have to pick in order to find that Mountain Dew preferring teen. Calculate P(X = 4).
(b) (Bonus:) I want to find 3 teens that favor Mountain Dew. I’m going to continue to pick teens until that happens. What is the probability that it take me 4 picks to find my third Mountain Dew favoring teen?
(c) Suppose I pick 3 teens at random. What is the probability that...
i. ... all 3 favor Mountain Dew?
ii. ... at least one favors Mountain Dew?