A student measures time for 20 oscillations of a simple pendulum as 30 ~s , 32 ~s , 35 ~s and 35 s . If the minimum division in the measuring clock is 1 s , then correct mean time (in second) is

Step-by-step solution

The mean time is calculated from the four measurements: 30 , s , 32 , s , 35 , s , and 35 , s . The average is T = 30 + 32 + 35 + 35 4 = 33 , s . The absolute deviations from the mean are 3 , s , 1 , s , 2 , s , and 2 , s . Their average gives the mean absolute error: T = 3 + 1 + 2 + 2 4 = 2 , s . Since the mean absolute error exceeds the clock's least count of 1 , s , it is appropriate for reporting uncertainty. Both the mean and its error are expressed to the same precision, yielding the result (33 2) , s . This