In determining monthly seasonal indexes for natural gas consumption,the sum of the 12 means for gas consumption as a percentage of the moving average is 1195.To get the seasonal indexes,each monthly mean is to be multiplied by (1195 / 1200).

Question

Quizplus · Accepted Answer

To get the seasonal indexes, each monthly mean as a percentage of the moving average should be divided by the sum of the 12 means (1195) and then multiplied by 100, not multiplied by (1195 / 1200). The correct formula for a seasonal index is (individual monthly mean / sum of all monthly means) * 100, assuming the sum of the indexes should equal 1200 (100 for each month).

In Determining Monthly Seasonal Indexes for Natural Gas Consumption,the Sum