High-pressure sales tactics or door-to-door salespeople can be quite offensive. Many people succumb to such tactics, sign a purchase agreement, and later regret their actions. In the mid-1970s, the Federal Trade Commission implemented regulations clarifying and extending the rights of purchasers to cancel such agreements. The accompanying data is a subset of that given in the article "Evaluating the FTC Cooling-Off Rule" (J. of Consumer Affairs, 1977: 101-106). Individual observations are cancellation rates for each of nine sales people during each of 4 years. Use an appropriate test at level .05 to see whether true average cancellation rate depends on the year.
