Suppose an experimenter wishes to evaluate the reliability of two weighing scales, by measuring a known 50-gram mass three times on each scale, and comparing the results. Scale A gives measurements of 49.8, 50.0 and 50.2 grams. Scale B gives measurements of 49.0, 50.0, and 51.0 grams. The average in both cases is 50.0 grams, so should the experimenter conclude that both scales are equally precise, on the basis of these data

Step-by-step explanation:

Precision refers to how close a set of measurements are when repeated severally in the same condition. It refers to the spread of the measured values .to find how precise a set of values are, we find the range first which is highest - lowest of each set of data  

Scale A = 50.2 - 49.8 = 0.4

Scale B = 51 - 49 = 2

the precision can be reported as Scale A = 50 ± 0.4 and scale B = 50 ± 2

The scale A is more precise than scale B, therefore the two scales does not equal precision.