# Calculations

The Calculation screen displays information of all the trials that have been completed. From this screen the Gauge Repeatability & Reproducibility report and Readings screen can be launched. Select a Part and its corresponding Parameter and click on the Report button to launch the Gauge Repeatability & Reproducibility Report. In this screen you need to choose Total Variation or Tolerance. Total Variation is calculated internally and displayed when you click on the Display Readings button. If Tolerance option is selected then you need to specify its value. Click on the Display Readings button to launch the Readings screen that displays all the readings of the Gauge Repeatability & Reproducibility study and its calculated values. No data on this screen can be added, modified or deleted.