Autocorrelation Charts
The Autocorrelation Function (ACF) is a tool for identifying dependence of current data on previous data points. It tests for correlation (in this case, autocorrelation) between observations of a given characteristic in the data set. You may notice a similarity between the formulas used for the autocorrelation function and the correlation index calculated in the Scatter Diagram. The Scatter Diagram is used to test for correlation between observations of different characteristics, while the ACF tests for correlation between observations of the same characteristic.
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