hii
fr this u have to find mean value of the time period first
= 2.63 + 2.56 + 2.42 + 2.71 + 2.80 / 5 = 2.624
2) Absolute error....
taking 2.624 as the true value of the tym period...
#T1 = 2.62 - 2.63 = - 0.01
#T2 = 2.62 - 2.56 = 0.06
#T3 = 2.42 - 2.62 = 0.20
#T4 = 2.62 - 2.71 = -0.09
#T5 = 2.62 - 2.80 = - 0.18
so
#T = -0.01 + 0.06 + 0.20 - 0.09 - 0.18 / 5 = -0.02/5 = -0.004
Fractional error = #T / T = - 0.004 / 2.62 = 0.0015
%age error = -0.0015 x 100 = 0.15%