Analysis of Percentage and Rating Scale Data

To many people, the subject of percentages is fraught with mystery, confusion, and paradox. A bank advertises that its interest rate on savings accounts is 10% higher than other banks in town which pay only 5%. Some investors are disappointed to learn that this new rate is not 15% but 5.5%. A farmer had a bad season and his potato yield decreased by 50% less than the year before. He figured that if he could increase his yield the next year by 50% he’d be back where he started. Was he right?