The Table Below Shows the Data on the Four Leading

Essay

The table below shows the data on the four leading indicators for the four-month period. Construct a diffusion index.
$$\begin{array} { | l | l | l | l | l | } \hline & { \text { Leading Indicators } } \\\hline \text { Month } & \text { A } & \mathrm { B } & \mathrm { C } & \mathrm { D } \\\hline 1 & 100 & 150 & 15 & 10 \\\hline 2 & 120 & 155 & 20 & 5 \\\hline 3 & 110 & 150 & 15 & 10 \\\hline 4 & 100 & 155 & 10 & 15 \\\hline\end{array}$$