Analysis of bottled water. Is the bottled water you’re drinking really purified water? A study of various brands of bottled water conducted by the Natural Resources Defense Council found that 25% of bottled water is just tap water packaged in a bottle (www.nrdc.

org). Consider a sample of five bottled-water brands, and let x equal the number of these brands that use tap water.

a. Explain why x is (approximately) a binomial random variable.

b. Give the probability distribution for x as a formula.

c. Find P1x = 22.

d. Find P1x … 12.