To maintain accuracy and precision of measurement, instruments used in laboratories and industrial firms are re-calibrated regularly at a calibration center where a standard measurement system is maintained under a highly controlled environment. However this periodic calibration does not guarantee that instruments will remain in a proper calibration status in between successive calibrations. Therefore, the status of a field instrument must be tested during the inter-calibration periods. Such type of tests is called an "assurance test".
The purpose of this thesis is to develop assurance testing procedure when the regions of the true values of test materials are known. The proposed procedure consists of hypothesis testing on the variance of measurement error and the parameters of the calibration equation. A method for determining the sample size to maintain the desired power is also presented.
