Question

• 4.29 The number of disk drives (in millions) made at a plant in Taiwan during the past 5 years follows: YEAR DISK DRIVES 140 160 nm + L 190 200 210 a) Forecast the number of disk drives to be made next year, using linear regression. b) Compute the mean squared error (MSE) when using linear regression. c) Compute the mean absolute percent error (MAPE). PX
Please provide hand-written explanation

Answer 1

4-28501:- Given, the number of disk drives (in millions) made at a plant in Taiwan during the past 5 years follows: Year Disk Drives 140 160 190 200 (@) Forecast - the number of disk drives to be made next year, using linear regression. observation production ty (40 140 160 320 190 570 200 800 5 5 210 1050 2-5 Total 1 900 55 2880 15 ezt EY Et2 Ety

s ry Ê = 2 = 3 му. is ŷ - Eyn = 180 o = Ity-nhŷ = 180 ß = 2t²_nê ² =10 slope (b) = = 18 Intercept (@) = ģ– bê = 126 so, the regression model is, Forecast (yt) = 18 period (+) +1267 So, for next year (ie.t=6) Fore cast (46) = 18 x6 +26 > Tove cast (78) = 234

Observation / year production, t²ty ty) forecast (4-18t+26 Error y-Y (Error) linear 140 1 140 144 regression. 2 160 4 320 162 - (b) The Mean Squared error (MSE) when using 100 180 4 200 16800 198 2 5 210 25 1050 216 160 Total 15 900 55 2880 SS Ey 3t It² sty

Mean Squared error (MSE) - SSE MSE = 160 = * MSE = 32 © The Mean absolute percent error (MAPE). - Lax Errorl / ervation / year/productionſ Forecast (t) 9 (4= 18€+126) | Error 4-Y) 0.029 1410 144 160 0,013 162 190 180 0.053 6 It lo lo 0.010 ū uw 200 198 0.029 20 26 0,132 Total 900 Mean absolute percent error, (MAPE) = 0132 - MAPE = 0.026