Statistics Meeting Book (March 20, 2019)

 the same operator;  the same measuring or test equipment used under the same

conditions;

 the same location;

ISO 2012 – All rights reserved 5 ISO/WD 15725-1 ISO/WD 15725-1  repetition over a short period of time. [ISO 3534-2:2006, clause 3.3.6] 3.15
repeatability standard deviation
 standard deviation of test results or measurement results obtained under repeatability conditions NOTE 1 It is a measure of the dispersion of the distribution of test or measurement results under repeatability conditions. NOTE 2 Similarly, “repeatability variance” and “repeatability coefficient of variation” can be defined and used as measures of the dispersion of test or measurement results under repeatability conditions. [ISO 3534-2:2006, clause 3.3.7] NOTE 3 Knowledge is needed of the probability distribution from which the value of the test result or the measurement result is regarded as drawn; often it can be taken as normal. 3.16
repeatability critical difference
 value less than or equal to which the absolute difference between two final values, each of them representing a series of test results or measurement results obtained under repeatability conditions, is expected to be with a specified probability E XAMPLE Examples of final results are the mean and the median of the series of results; the series itself may consist of only one result. [ISO 3534-2:2006, clause 3.3.8] NOTE The calculation of a repeatability critical difference usually requires a known or assumed distribution for differences. 3.17
repeatability limit
 repeatability critical difference for a specified