Average prices represent, quite simply, total sales revenue divided by total units sold. Many products, however, are sold in multiple variants, such as bottle sizes. In these cases, managers face a challenge: they must determine 'comparable' units. Average prices can be calculated by weighting different unit selling prices by the percentage of unit sales (mix) for each product variant. If we use a standard, rather than an actual mix of sizes and product varieties, the result is price per statistical unit. Statistical units are also known as equivalent units. Average price per unit and prices per statistical unit are needed by marketers who sell the same product in different packages, sizes, forms, or configurations at a variety of different prices. As in analyses of different channels, these product and price variations must be reflected accurately in overall average prices. If they are not, marketers may lose sight of what is happening to prices and why. If the price of each product variant remained unchanged, for example, but there was a shift in the mix of volume sold, then the average price per unit would change, but the price per statistical unit would not. Both of these metrics have value in identifying market movements. In a survey of nearly 200 senior marketing managers, 51 percent responded that they found the "average price per unit" metric very useful in managing and monitoring their businesses, while only 16 ound "price per statistical unit" very useful.