What equation is used for XRF calibration compliance?

The equation used for XRF (X-ray fluorescence) calibration compliance is based on the average of three readings compared to the NIST (National Institute of Standards and Technology) film value. This method is established to ensure that the calibration of the XRF instrument provides reliable and accurate measurements.

Taking the average of three readings allows for a balance between precision and practicality. It helps account for any variations or outliers in the measurements, thus giving a more robust estimate of the true value. This approach reduces the influence of random error while still being manageable in terms of time and resource use. Moreover, using three readings is a standard practice in many calibration procedures, as it conforms to statistical norms that govern quality assurance in analytical measurements.

The choice of the number of readings is critical, as fewer readings might not sufficiently account for variability, while more readings might unnecessarily complicate the process without providing significant benefits. Therefore, averaging three readings strikes the right balance in this context, making it the correct approach for XRF calibration compliance.