Here is a process that I found online and adapted to a spreadsheet to calculate Gage R&R based on Average and Range

Average and Range TMV calculations

This is how its calculated:

This section describes the calculation method used to evaluate the test results from the Gauge R and R studies.

- Test is conducted according to the required test protocol and data is collected. Four data forms should be filled , two by each operator who should conduct two different tests.
**Operator Range for each device**will be calculated for each operator by subtracting the minimum measurement from the maximum measurement**Operator Average for each device**will be calculated for each operator by adding the two measurements taken for the same device by each operator and dividing them by two (Number of trials).- The
**average operator range for each operator**will be calculated by adding all the ranges for each device and dividing them by 10 (number of devices tested). - The
**average operator average**measurement for each operator will be calculated by adding the average for each device and dividing them by 10 (number of devices tested) **Part average**will be calculated by adding all the measurements for the same device and dividing them by 4 (number of trials by number of operators).**Part range**will be calculated by subtracting the minimum measurement for each part to the maximum measurement for each device.**Operators average range (R)**will be calculated by adding both*average operators range*and dividing them by two.**Operators range (X)**will be calculated by subtracting the minimum*average operator range*from the*maximum average operator range.***Range of parts (Rp)**will be calculated by subtracting the minimum*part average*from the maximum*part average.***K values**will be used from table 4.3.1.1**Equipment variation****EV)**will be calculated by using this formula:

EV= R * K1

**Appraiser variation (AV)**will be calculated by using this formula: (n= number of devices, r =number of trials

AV=

**Repeatability and****(R&R)**will be calculated by using this formula:

R&R=

**Part variation (PV)**will be calculated by using this formula:

PV= Rp * K3

**Total Variation (TV)**will be calculated by using this formula:

TV=

**Percentage of variation will be calculated as follows:**

%EV = EV / TV

%AV = AV / TV

% R&R = R&R/ TV

% PV = PV/ TV

- Repeatability—How much variability in the measurement system is caused by the measurement device.
- Reproducibility—How much variability in the measurement system is caused by differences between operators.

So, we want to see how much adding this two together can affect the “quality “ of the measurements, and this is what validates a test method.

Good luck!