Time Periods
the Following Are the Values of a Time $$\begin{array} { | c | c c c c | } \hline \boldsymbol { t } & 1 & 2 & 3 & 4 \\\hline y _ { t } & 23 & 25 & 28 & 24 \\\hline\end{array}$$

Time periods
The following are the values of a time series for the first four time periods: $$\begin{array} { | c | c c c c | } \hline \boldsymbol { t } & 1 & 2 & 3 & 4 \\\hline y _ { t } & 23 & 25 & 28 & 24 \\\hline\end{array}$$
-Suppose that we calculate the four-period moving average of the following time series $$\begin{array} { | c | c c c c c c | } \hline \boldsymbol { t } & 1 & 2 & 3 & 4 & 5 & 6 \\\hline y _ { t } & 16 & 28 & 21 & 15 & 26 & 12 \\\hline\end{array}$$ What is the centered moving average for period 3?