1. Exploratory Data Analysis 1.2. EDA Assumptions 1.2.5. Consequences 1.2.5.3. Consequences of Non-Fixed Variation Parameter
Variation Estimate	The usual estimate of variation is the standard deviation from N measurements Y1, Y2, ... , YN.
Consequences of Non-Fixed Variation	If the run sequence plot does not support the assumption of fixed variation, then The variation may be drifting. The single variation estimate may be meaningless (if the process variation is drifting). The variation estimate may be incorrect. The variation estimate may be biased.