Laboratory Quality Control Practice Test 2026 – The Comprehensive All-in-One Guide for Exam Success!

When you want to express how much a set of measurements varies relative to its average, you use the coefficient of variation. This measure puts the variability in a percentage of the mean, giving a unitless value that allows comparing precision across different datasets or instruments with different scales. It’s calculated as the standard deviation divided by the mean, then multiplied by 100.

This is why it’s the best choice here: it directly expresses dispersion as a percent of the mean, unlike standard deviation, which is an absolute spread in the same units as the data and isn’t readily comparable across datasets with different means. Precision concerns how consistently measurements are repeated and is related to variability, but it’s not itself the percent-of-mean expression. Accuracy describes closeness to the true value, not how spread out the measurements are. Keep in mind that a very small mean can inflate the coefficient of variation, so interpretation should consider the context.