For predicting the straight line trend in the sales of cars (in thousands) on the basis of 5 consecutive years' data, the company makes use of a 3-year moving averages method. If the sales of the cars for respective years are 15, 24, 18, 33 and 42 respectively, then which of the following averages will not be computed?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 32
A 3-year moving average is the mean of three consecutive years; the window then moves on by one year. Five years give three averages:
\( \displaystyle \frac{15 + 24 + 18}{3} = \frac{57}{3} = 19 \)
\( \displaystyle \frac{24 + 18 + 33}{3} = \frac{75}{3} = 25 \)
\( \displaystyle \frac{18 + 33 + 42}{3} = \frac{93}{3} = 31 \)
The averages computed are 19, 25 and 31, so 32 is not computed.