The length of a straight line is measured a number of times by a number of observes . The following are the results of these measurements. Decide precision and accuracy.
Actual length = 3.785 cm `pm 0.001 ` cm
1st set of measurement 3.8 cm , 3.9 cm , 3.7 cm
2nd set of measurements 3.478 cm , 3.479 cm , 3.478 cm , 3.478 cm , 3.479 cm
3 rd set of measurement 3.55 cm , 3.65 cm , 3.45 cm , 3.45 cm , 3.35 cm 4th set of measurements 3.784 cm , 3.785 cm , 3.784 cm , 3.785 cm , 3.784 cm

Explanation

First set of measurements are accurate because it is closest to the actual value but not precise. Second set of measurements are not accurate but it is most precise because the reading are reproducible.
Third set of measurements are neither accurate nor precise.
Fourth set of measurements are accurate as well as precise.