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

Day	Clock $1$	Clock $2$
Monday	$12:00:05$	$10:15:06$
Tuesday	$12:01:15$	$10:14:59$
Wednesday	$11:59:08$	$10:15:18$
Thursday	$12:01:50$	$10:15:07$
Friday	$11:59:15$	$10:14:53$
Saturday	$12:01:30$	$10:15:24$
Sunday	$12:01:19$	$10:15:11$

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

(B) To determine the precision of the clocks,we calculate the range of variation for each clock over the seven days.
For Clock $1$,the readings range from $11:59:08$ to $12:01:50$. The total variation is $162 \; s$.
For Clock $2$,the readings range from $10:14:53$ to $10:15:24$. The total variation is $31 \; s$.
Precision in an experiment depends on the consistency of the clock,not its absolute accuracy (zero error),as a constant zero error can be easily corrected by calibration.
Since Clock $2$ has a much smaller variation $(31 \; s)$ compared to Clock $1$ $(162 \; s)$,it is more precise.
Therefore,Clock $2$ is preferred for precision time interval measurements.