A Time Series Analysis Was Performed to Determine the Number

A time series analysis was performed to determine the number of new online customers that joined the 'Jelly of the Month Club'.The actual number of new customers, the forecast values and the error terms are presented in the following table.The mean error (ME) for this forecast is ___________. $\begin{array}{|r|r|r|r|}\hline \text { Monthh } & \text { Actual } & \text { Forecast} & \text { Error } \\\hline \text { July } &4 & & \\\hline \text { Aug } & 6 & 5 &-1 \\\hline \text { Sept } & 3 & 6 &3 \\\hline \text { Oct } & 9 & 8& -1 \\\hline \text { Nov } &8 &9& 1 \\\hline\end{array}$

A) -0.50
B) 0.50
C) 1.50
D) 7.00
E) 3.00