TABLE 16-13 Given Below Is the Monthly Time-Series Data for U.S.retail Sales

Short Answer

TABLE 16-13
Given below is the monthly time-series data for U.S.retail sales of building materials over a specific year. The results of the linear trend,quadratic trend,exponential trend,first-order autoregressive,second-order autoregressive and third-order autoregressive model are presented below in which the coded month for the 1^st month is 0:
Linear trend model: Quadratic trend model: Exponential trend model: First-order autoregressive: Second-order autoregressive: Third-order autoregressive: Below is the residual plot of the various models:
-Referring to Table 16-13,what is the exponentially smoothed forecast for the 13^th month using a smoothing coefficient of W = 0.5 if the exponentially smooth value for the 10^th and 11^th month are 9,746.3672 and 9,480.1836,respectively?