Does the kid factor make a difference? If you are talking photography, the answer may be yes. Ages of children in household, years: under 2 and the percent of U.S household that buy film is 75%. Ages of children in household, years: none under 21 and the percent of U.S household that buy film is 40%. Let us say you are a market research person who interviews a random sample of 10 households. Suppose you interview interview 10 households with children under the age of 2 years. Let r represent the number of such households that buy film. Make a histogram showing the probability distribution of r for r = 0 through r=10