Statistical Question

Liam_Jenkins_99

The trend in a firm's sales is for an increase of 2% per quarter.

Quarter 1:
Trend - 48,000.
Seasonal Variation - +10%.
Actual Sales - 52,800.

Quarter 2:
Trend - 48,960.
Seasonal Variation - +25%.
Actual Sales - 61,200.

Quarter 3:
Trend - 49,939.
Seasonal Variation - -5%.
Actual Sales - 47,442.

Quarter 4:
Trend - 50,938.
Seasonal Variation - -30%.
Actual Sales - 35,657.

How is the Seasonal Variation -30% for Quarter 4?

davealucas

Seasonal variations should, when added together, come back to zero.

In your case, the three seasonal variations come to +30% when added together. Therefore the final variation must be -30%

Liam_Jenkins_99

Thank you Dave.