Repeatability and reproducibility in the precision of national standard

Repeatability does not refer to your results, but rather to the experimental data obtained by others with the same instrument and experimental methods compared with your results. This is the determination of the C content of steel, but you can learn from it

Repeatability accuracy of the instrument

Select a national steel standard material (carbon content in the range of 0.400% ~ 1.000%, sulfur content in the range of 0.020% ~ 0.080%), according to the instrument instruction manual of the specified operating method operation, five consecutive tests, the test results of the maximum value and the minimum value between The difference between the maximum value and the minimum value should be less than or equal to 1.4r, r is calculated by the following formula:

Carbon: 1gr = 0.521211gm-1.9617

Sulfur: 1gr = 0.622121gm-1.9965

Where r indicates the Repeatability, m indicates the calibration value of the measured substance.

Accuracy of the instrument

Select the national level (steel or iron) standard material high, medium and low three content samples each bottle (carbon content in the range of 0.050% ~ 4.500%, sulfur content in the range of 0.005% ~ 0.300%). According to the operating method specified in the instrument instruction manual, each standard material test three times, take the average value of three times, the average value and the calibration value of the difference between the absolute value of less than or equal to the calculated value of CrD95, see the following formula:

This formula is not good to get up, go to the check yourself ah sorry.

The formula denotes the average value, denotes the calibration value of the substance under test, n denotes the number of tests, r denotes repeatability, and R denotes reproducibility. The formula for the reproducibility R is as follows:

Carbon: 1gR = 0.582211gm-1.4558

Sulfur: 1gR = 0.688781gm-1.3693

where m denotes the calibrated value of the substance under test.