In instances when there is a lot of data variability, a rolling window function will enable you to use a statistical value to represent the values.
Periods and Min Periods are the windows used to calculate the statistics value.
Periods represent the length of the granularity selected in the TIME panel. For example, if "days" is selected with a setting of 7 for "Periods", then the function will be based on 7 days.
Min Periods should be identical to Periods to ensure that every data point is calculated with the same value.
- Mean: The average of all values within a period.
- Sum: The sum of the value in the period specified.
- Std: This means Standard Deviation, which represents the dispersion of the data relative to its mean for the rolling window period.
- CumSum : This means Cumulative Sum, which show the cumulative data — it does not require period or min period values.
This case represents the number of new cases reported per day per country for the top 10 countries. New cases per day fluctuate day-by-day and, consequently, it is very difficult to see trends.
Rolling functions support a better representation of data by representing the moving average in a 10-day period. This facilitates the easier identification of trends.
Cumulative Data Over a Period of Time
With rolling windows, it is also possible to look at cumulative data over time.