Final answer:
The analyst expressing confidence that his method produced a result 4% off from the NIST value indicates confidence in the accuracy of his measurement, which means the results are close to the true value.
Step-by-step explanation:
When the analyst reports that his analytic method produced a result which is 4% off from the National Institute of Standards and Technology (NIST) reported standard value, he is expressing confidence in the accuracy of his measurement. Accuracy refers to how close a measurement is to the correct or accepted reference value. In science, accurate measurements are vital as they provide data that are close to the true value or the standard value established, for instance, by the NIST. Since the analyst's measurements are close to the standard NIST value, despite the 4% discrepancy, they can be considered accurate within a reasonable margin of error. However, without additional information about the variability or reproducibility of his measurements, nothing can be said about their precision. Precision would refer to whether repeat measurements under unchanged conditions produce the same results.