Q$2.$ Global smartphone sales experienced extraordinary growth starting in $2007$ with the introduction of both the iPhone and Android$-$platform based devices. Following are the yearly global sales $($in million units$)$ for smartphones beginning in $2008$ through $2015$ :

$\backslash$table$[[$#$,$YEAR,SALES$],[1,2008,145\mathrm{.}00],[2,2009,172\mathrm{.}38],[3,2010,320\mathrm{.}00],[4,2011,472\mathrm{.}00],[5,2012,950\mathrm{.}35],[6,2013,1000\mathrm{.}72],[7,2014,1244\mathrm{.}74],[8,2015,1423\mathrm{.}90]]$

Linear model $(hat(y))=38\mathrm{.}63+149\mathrm{.}92**x_i$

a $(3$ pts$).$ Forecast smartphone sales for $2016,2017,2018,2019,$ and $2020$ by using the linear model $(hat(y))($above$)$

$\backslash$table$[[$#$,$YEAR,Actual sales,Linear model$],[1,2008,150\mathrm{.}00,],[2,2009,172\mathrm{.}38,],[3,2010,320\mathrm{.}00,],[4,2011,500\mathrm{.}00,],[5,2012,950\mathrm{.}35,],[6,2013,1200\mathrm{.}00,],[7,2014,1244\mathrm{.}74,],[8,2015,1423\mathrm{.}90,],[9,2016,,],[10,2017,,],[11,2018,,],[12,2019,,],[13,2020,,]]$

B $(3$ pts$).$ Calculate Mean Absolute Percentage error $($MAPE$)$ for five years $($Using two decimals$)$

$\backslash$table$[[$Year$,$Actual sales,$**$ Forecasted sales,Forecast Error,Absolute Percentage Error$],[2016,1495\mathrm{.}96,,,],[2017,1536\mathrm{.}54,,,],[2018,1650\mathrm{.}27,,,],[2019,1700\mathrm{.}00,,,],[2020,1800\mathrm{.}00,,,]]$

$(**$ The forecasted sales is predicted by the linear model from question a$)$