The Quarterly Sales ($Millions) of a Department Store Chain Were

Essay

The quarterly sales ($millions) of a department store chain were recorded for the years 1995-1998. $$\begin{array} { | c | c c | } \hline \text { Year } & \text { Quarter } & \text { Sales } \\\hline 1995 & 1 & 21 \\& 2 & 36 \\& 3 & 28 \\& 4 & 44 \\1996 & 1 & 25 \\& 2 & 23 \\& 3 & 39 \\& 4 & 36 \\1997 & 1 & 30 \\& 2 & 41 \\& 3 & 47 \\& 4 & 55 \\1998 & 1 & 34 \\& 2 & 29 \\& 3 & 32 \\& 4 & 48 \\\hline\end{array}$$ a. Calculate the four-quarter centred moving averages.
b. Graph time series and moving averages. State your conclusions about time-series smoothing?