=+39. eBay. An Australian collector purchased a quantity of cricket cards and is going to sell them on eBay. He has 19 Ashes Cricket Card sets. In recent auctions, the mean selling price of such cards has been $12.11, with a standard deviation of $1.38. He also has 13 Australian Champion Cricketers signed index cards which have had a mean selling price of $10.19, with a standard deviation of $0.77. His insertion fee will be $0.55 on each item, and the closing fee will be 8.75% of the selling price. He assumes all will sell without having to be relisted.