It’s all about the measurement variations and correcting the factors that contribute on it. Measurement variations can come from three main sources: the person using the gage, person to person and part to part. It is also the gage itself a factor. MSA studies exist to discover and quantify the amount of variation coming from these different sources, so that corrective action may be taken if necessary. There are too many formulas of Gr&R studies. It depends from our intention: 1) To discover the amount of variation coming from three main sources. We need the data of one dimension-measurements(a) of three persons(b) for 10 parts(c), taken from Measurement Systems Analysis Reference Manual, 3rd edition (Chrysler, Ford, General Motors Supplier Quality Requirements Task Force). Ten parts were selected that represent the expected range of the process variation. Three operators measure the ten parts, three times per part, in a random order. 2) To examine the accuracy of a gauge, how a