Question $3$: $(15$ points$)$

The historical demand data for snow ski bibs are shown below. Create a seasonal forecast by addressing the questions below. Show work for full credit. Use regular rounding rules to up to four decimal places for best results.

a$.$ What is the deseasonalized periodic demand?

b$.$ What are the seasonal indices for each period? $($Use regular rounding rules to up to four decimal places for best results$)$

c$.$ If the demand for next year is estimated to be $1200$ bibs, what is the seasonal forecast for each period $($in whole units using regular rounding rules$)?$

$\backslash$table$[[$Period$,$Historical Avg. Demand,Seasonal Indices,Next Year Forecast$],[1.$ January $/$ Feb.,$190,,],[2.$ March $/$ April,$80,,],[3.$ May $/$ June,$60,,],[4.$ July $/$ August,$60,,],[5.$ Sept. $/$ Oct.,$195,,],[6.$ Nov. $/$ Dec.,$375,,],[$TOTAL$,960,,]]$