Missing Data with Individual Observations
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If an observation is missing, there is a gap in the Individuals chart where that observation would have been plotted. When calculating moving ranges, each value is the range of K consecutive observations, where K is the length of the moving ranges. If any of the observations for a particular moving range are missing, it is not calculated. Hence, there is a gap in the Moving Range chart corresponding to each of the moving ranges that includes the missing observation.