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I". Di rearsia-Di mam see 14' Suppose you want to estimate the effect of Philadelphia's sugar tars: which imposes a 1.5 cent per ounce tart on sugar sweetened beverages. To do so: you collect data on monthly purchases of sugar sweetened beverages {in oz.) for the cities of Philadelphia and Pittsburgh? the latter of which does not have a sugar tax. The following table presents average purchases of sugar sweetened beverages. Philadelphia Pittsburgh {Treatment Group} {Control Group) 1. By how much do monthly sugar sweetened beverage purchases change over time in Philadelphia? 2. By how much do monthly sugar sweetened beverage purchases change over time in Pittsburgh? 3. Using your answers to {1 .j and {2.): what is the difference-indifferences esmate of the effect of the sugar tan on monthly sugar sweetened beverage purchase? Hint: Subtract your answer to {2.} from your answer to {1 .j. 4. You decide to estimate a simple regression model that does not include any control variables. Using the following regression line: pur'chhseslr = 1?.25 1.5trerxtmentf + 1.25;!\"der treutment * nostfh what ig the differenceindifferences estimate of the effect of the sugar tax on monthly sugar sweetened beverage purchase? 5. Is your answer to {4.} the same as your answer to {5.}