According to the Federal Communications Commission, 70% of all U.S. households have vcrs. In a random sample of 15 households, what is the probability that fewer than 13 have vcrs?
A) 0.1268
B) 0.7
C) 0.8732
D) 0.5

Question

Quizplus · Accepted Answer

This is a binomial probability problem where we are looking for the probability of x < 13 successes (households with VCRs) in n = 15 trials (households), with the probability of success on a single trial (p) being 0.7. The probability of fewer than 13 households having VCRs is found by calculating 1 minus the probability of 13, 14, or all 15 households having VCRs. The correct answer, 0.8732, represents the cumulative probability of getting 0 to 12 households with VCRs out of 15, which is the complement of getting 13, 14, or 15 households with VCRs.

According to the Federal Communications Commission, 70% of All U