Seasonal Index Methods

Average Method - This method simply calculates an average for each day of the year. It therefore has the same units as the underlying commodity.

Link Relative Method - This method requires the following steps:

1. Express each daily close as a percentage of the previous day's close.
2. Average these percentage values for each day of the year.
3. Set the first day of the seasonal to 100% and reexpress all the other daily averages as relative percentages of the first day's value.

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