What is the Absolute percent error for period $4$ when Three period moving average forecast method is used:$($Please round to $2$ decimal places for your answer$).$ Do Not convert to percentage, leave as a decimal value.

$\backslash$table$[[$Week or$,$Time series value,,$],[$X$($Time Period$),$or $Y($Sales$),$Forecast,$],[1,5\mathrm{.}2,,],[2,7\mathrm{.}4,,],[3,2\mathrm{.}1,,],[4,11\mathrm{.}0,,],[5,15\mathrm{.}2,,],[6,12\mathrm{.}2,,],[7,,,]]$