Suppose that we calculate the four-period moving average of the following time series: $$\begin{array} { | c | c c c c c c | }
\hline t & 1 & 2 & 3 & 4 & 5 & 6 \
\hline y _ { t } & 18 & 28 & 23 & 17 & 26 & 14 \
\hline
\end{array}$$ The centred moving average for period 4 is:
A) 20.00.
B) 22.50.
C) 23.50.
D) 21.75.

Question

Suppose that we calculate the four-period moving average of the following time series: $$\begin{array} { | c | c c c c c c | } 
\hline t & 1 & 2 & 3 & 4 & 5 & 6 \
\hline y _ { t } & 18 & 28 & 23 & 17 & 26 & 14 \
\hline
\end{array}$$ The centred moving average for period 4 is:
A) 20.00.
B) 22.50.
C) 23.50.
D) 21.75.

Quizplus · Accepted Answer

To calculate the four-period moving average, we take the average of the last 4 values:
- For period 4: (18+28+23+17)/4 = 21.50
- For period 5: (28+23+17+26)/4 = 23.50
- For period 6: (23+17+26+14)/4 = 20.00

To calculate the centred moving average for period 4, we take the average of the two closest moving averages around period 4:
- For period 4: (21.50+23.50)/2 = 22.50

Therefore, the best choice is D, as it corresponds to the centred moving average for period 4.

Suppose That We Calculate the Four-Period Moving Average of the Following