Originally Posted by
MinnMan
accuracy: Is the measurement reflecting the true value of the parameter.
precision: Does the measurement give high repeatability within a small window of uncertainty.
If I measure something, let's say mass, and I always get the same result within a small window, say, 153.56±0.01 grams, then I have a precise measurement. It may not be at all accurate - the true mass could be 159 grams. If I use a different balance and I get masses that vary from measurement to measurement, but centered about the true mean, say 158.5±1.5 grams, then the second balance is more accurate but less precise.
So the measurement in question, % body fat, appears to be fairly precise, without any constraints on accuracy.
Exactly. This is why I always use the same scale, and tend to think more in terms of the weight I've lost rather than the weight I AM. Also why I weigh myself at the same time of day.
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