Anne is a bargain-minded shopper. Normally, her favorite toothpaste costs the same at both of her local supermarkets, but the stores are having competing sales this week. At one store, there is a bonus offer: buy 3, get 1 free. At the other store, toothpaste is being sold at 30 percent off. Anne instantly opts for the first offer. Was that really the less-expensive choice?

a. Explain showing your calculations

b. Give an example where you have made a decision-making error. What type of bias/fallacy was illustrated. Use chapter 8 to support.