Errors of Measurement
To ensure the quality of a product, errors of measurement is very important, as test cases are executed at various levels defects if found any in the tested area. The defects are logged and data is collected. The defects are then fixed. The testing team verifies if the defect was really fixed and closes the defects. This information is very beneficial. Proper tracking ensures that all defects were fixed. This information also helps in future projects.
Variation in a process has two sources:
Even when rightly used, a measuring instrument may not give a true reading of a characteristic. The distinction between the true value and the measured value can be due to one or more five sources of variation.
Bias is the difference between the observed average of measurements and the reference value. The reference value is also termed as accepted reference value or master value. It is a value that serves as an agreed-upon reference for the measured values.
Any statement of bias and repeatability must be preceded by three conditions:
Errors of measurement can cause incorrect decisions on:
In the classification of a product, two types of errors can occur, they are: