Expressing experimental error. In an experiment to measure the acceleration of gravity at the surface of the earth in the DFW Metroplex, 9.85 m/s2 (E1) and 9.73 m/s2 (E2) are obtained. The accepted local value of g = 9.80 m/s2 (A) for DFW.

Question

Expressing experimental error.  In an experiment to measure the acceleration of gravity at the surface of the earth in the DFW Metroplex, 9.85 m/s2 (E1) and 9.73 m/s2 (E2) are obtained. The accepted local value of g = 9.80 m/s2 (A) for DFW.  
What is the % difference for the measurements?     
What is the % error of the first measurement E1?    
What is the % error of the second measurement E2?

Anonymous · Answer

100(9.85 -9.73)/ (9.85+9.73)/2 = 12/9.79 = 1.23 % 100(9.85-9.80) / 9.80 = 0.51 % 100(9.73-9.80)/9.80 = -0.71 %