The Number of Properties Newly Listed with a Real Estate

Essay

The number of properties newly listed with a real estate agency in each quarter over the last four years is given. Calculate the seasonal index values. $$\begin{array} { c | r r r r } &{ \text { Year } } \\\text { Quarter } & 1 & 2 &{ 3 } & { 4 } \\\hline 1 & 73 & 81 & 76 & 77 \\2 & 89 & 87 & 85 & 92 \\3 & 123 & 115 & 108 & 131 \\4 & 92 & 93 & 87 & 101\end{array}$$