Missing Data
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Gage R&R Study (Crossed) and Gage R&R Study (Nested) both require balanced designs (equal numbers of observations per cell) and replicates to calculate the variance components. If you have missing data, you can use Gage R&R Study (Expanded) to analyze the unbalanced design.

Alternatively, you can estimate the missing observations. See [7] for estimation methods. After you have estimated the missing observations, Gage R&R Study (Crossed) and Gage R&R Study (Nested) can analyze the data as a balanced design.