Seventy dash five percent of consumers prefer to purchase electronics online. You randomly select 8 consumers. Find the probability that the number of consumers who prefer to purchase electronics online is (a) exactly five, (b) more than five, and (c) at most five.

(a) 5/8

(b) 3/8

(c) 1

Explanation:

Probability is given by number of possible outcomes : number of total outcomes

(a) Number of possible outcomes = 5, number of total outcomes = 8

Probability (exactly five) = 5/8

(b) Probability (more than five) means that the number selected is not exactly five = 1 - Probability (exactly five) = 1 - 5/8 = (8 - 5) / 8 = 3/8

(c) Probability (at most five) means that the number selected is either less than five (not exactly five) or exactly five = Probability (not exactly five) + Probability (exactly five) = 3/8 + 5/8 = (3+5) / 8 = 8/8 = 1