The iTunes store, owned by Apple Inc. sells songs, movies and tv shows. These stores operate in several countries and the songs are priced in local currency terms. iTunes Song PPP exchange Price Rate (Local currency) US$ 0.99 USA Australia Canada Japan UK Source: The Economist A$1.69 C$0.99 200 0.79 A$1.70 C$1 202 0.79 Current US$ exchange rate A$1.33 C$1.12 112 0.53 Over (+)/under (-) Over (+)/under (-) valuation valuation (iTunes) (Big Mac)* +28% -11% +80% +51% -21% +1% -28% +18% What factor(s) could potentially explain the different prices charged for songs on iTunes? What advantage does the iTunes index have over the Big Mac index? (4 points; Max 200 words)