A firm uses a simple exponential smoothing method with a smoothing constant of $0\mathrm{.}15$ for estimating the demand for a particular product. The actual demand for six months is available. The forecast for June is $500$ units. Estimate the forecast for December. Calculate Mean Absolute Deviation $($MAD$)$ and BIAS if the actual demand for December is $510$ units.

$\backslash$table$[[$Months$,$Jun,Jul,Aug,Sep,Oct,Nov$],[$Actual Demand,$450,505,516,488,467,554]]$