Two clocks are being tested against a standard clock located in a national laboratory. At 12:00:00 noon by the standard clock , the readings of the two clocks are :

If you are doing an experiment that requires 'precision time interval' measurements, which of the two clocks will you prefer? c

Explanation

The range of vairation over the seven days of observation is 164 s for clock 1, and 32s for clock 2. The average reading of clock 1 is much closer to the standard time than the average reading of clock 2. The important point is that a clock is zero error is not as significant for percision work as its variation, because a .zero-error. can always be easily corrected. Hence clock 2 is to be preferred to clock 1.