Seasonal fluctuations. Indices seasonality. The method of constant mean
Learning from regular (seasonal) fluctuations using the online calculator on our website. Seasonality index is calculated by the method of constant mean.
It is worth noting that the average indices of the season - it's such analytical indicators of time series, which is characterized by seasonal fluctuations.
Seasonal fluctuations, in turn - it intrayear changes each time re-changed to the phenomenon under study.
Describe the seasonal variation, you can use the seasonality indices, which are calculated as a ratio of the actual value of the indicator to the theoretical level.
i - there is a serial number of the seasonal cycle (year)
j - serial number within-period (month)
It all comes down to the calculation of the average seasonality indices for each period (year or month):