A researcher wants to study the effect of a price change on the sales of various brands of a certain product. Assume the market is made up of four brands W,X,Y and Z and the price change (decrease) for brand W is introduced immediately after time t 0 . Assume every respondent buys exactly one unit of the product in each period. Data on number of respondents buying each brand in each period, based on a panel, are as follows: Note: Confine your attention only to the data presented. Assume the world starts at t0 and stops after t1 and the strategies of brands X,Y, and Z are unchanged between t0 and t1. a) On the basis of these data, is the price change for brand W successful? Focus on market share as the relevant criterion. Show your calculations. ( 8 points) (Note: Market share is the percent of total sales in an industry that generated by a particular company)