The range chart indicates that the gage variability is consistent. The average chart indicates that the measurement system is adequate to detect part-to-part variation. Now you can perform a statistical analysis. Which analysis method should you choose: average and range, or variance components?

Since the data for this study are balanced (no data points are missing), the average and range method can be used. But it is not as efficient as the variance components method, and it does not provide information about the interaction between operators and parts. Both methods will be shown to illustrate some of these differences.