Question: Choose an American household at random and let the random variable X be the number of cars (including SUVs and light trucks) they own. Here is the probability model if we ignore the few households that own more than 5 cars:
about what percentage of households have a number of cars within 2 standard deviations of the mean?
(a) 68%
(b) 71%
(c) 93%
(d) 95%
(e) 98%