Anewspaper story on the effect of higher milk prices on the market for ice cream contained the following: "as a result [of the increase in milk prices], retail prices for ice cream are up 4 percent from last year. . and ice cream consumption is down 3 percent." source: john curran, "ice cream, they scream: milk fat costs drive up ice cream prices," associated press, july 23, 2001. based on the information given, what is the price elasticity of demand for ice cream?