$12\mathrm{.}3.$ Given the following data, calculate the average $x$ of the distribution and the standard deviation $().$

$\backslash$table$[[$Period$,\backslash$table$[[$Actual$],[$Demand$]],$Deviation,$\backslash$table$[[$Deviation$],[$Squared$]]],[1,500,,],[2,600,,],[3,425,,],[4,450,,],[5,600,,],[6,575,,],[7,375,,],[8,475,,],[9,525,,],[10,475,,],[$Total$,,,]]$