Given the Following Time Series, Compute the Seasonal (Quarterly) Indexes

Essay

Given the following time series, compute the seasonal (quarterly) indexes, using the four-quarter centred moving averages. $$\begin{array} { | c | c c c c c | } \hline \text { Quarter } & 2011 & 2012 & 2013 & 2014 & 2015 \\\hline 1 & 62 & 48 & 50 & 43 & 57 \\2 & 51 & 45 & 46 & 39 & 32 \\3 & 53 & 44 & 46 & 37 & 31 \\4 & 46 & 37 & 42 & 32 & 29 \\\hline\end{array}$$