Answer and Explanation:
a. The computation of the percent difference between the measurements is shown below:-
The first value of g is 9.67 and the second value is 9.88
So, difference = 9.88 - 9.67
= 0.21
Percentage difference in measurement is

= +/-2.13
Percent difference with 9.88
Difference = 9.88 - 9.81
= 0.07

= +/-0.71%
b. The Computation of percent error of their mean is shown below:-
Mean of two values is
=

= 9.775
Difference = 9.81 - 9.775
= 0.035
Percentage difference is

= +/- 0.36%