Gage R&R Folio: Analysis Results

The Analysis of Variance (ANOVA) table includes the following columns:

1. • Source of Variation is the source that caused the difference in the measurements. Part(Operator) is the part variation within operators, and it is shown only for nested designs.

   • The number of Degrees of Freedom is the number of regression coefficients in the regression model for this source of variation.

   • Sum of Squares is the amount of difference in measurements caused by this source of variation.

   • Mean Squares is the average amount of difference caused by this source of variation. This is equal to Sum of Squares/Degrees of Freedom.

   • F Ratio is the ratio of Mean Squares of this source of variation and Mean Squares of pure error. A large value in this column indicates that the difference in the output caused by this source of variation is greater than the difference caused by noise (i.e., this source affects the output).

   • P Value (alpha error or type I error) is the probability that an equal amount of variation in the measurements would be observed in the case that this source does not affect the output. This value is compared to the risk level (alpha) that you specify on the Analysis Settings page of the control panel. If the p value is less than alpha, this source of variation is considered to have a significant effect on the output. In this case, the term and its p value will be displayed in red.

This table includes the following columns:

1. • Source is the source of variation in the measurements. Total Gage R&R is the sum of Repeatability and Reproducibility, and Total Variation is the sum of Total Gage R&R and Part. Part(Operator) is the part variation within operators and is shown for nested designs.

   • The Variance Results section includes these columns:

   • • Variance is a measure of how far the measurements are spread out due to this source of variation.

     • Variance Contribution is the percentage of variance that is due to this source of variation.

   • The Standard Deviation section includes these columns:

   • • Standard Deviation is the standard deviation that is due to this source.

     • Standard Deviation Ratio (%) is the percentage of the total standard deviation that is due to this source.

     • Study Variation represents the spread of values that could result from this source of variation. It is equal to 6 * the standard deviation.

     • Study Variation to Tolerance Ratio is the Study Variation divided by the process tolerance specification entered on the Analysis Settings page of the control panel. Thus, a ratio of 100% means the variation in measurements is equal to the acceptable range of part values.