Question

The refractive index was found to be 1.54, 1.53, 1.51, 1.50, 1.52 in a successive measurement .calculate the refractive index of glass and the percentage error in its measurement

Answer 1

average value of measurements = (1.54+1.53+1.51+1.50+1.52)/5=1.52
the precision = 0.01 as the values are measured to the 2nd decimal place...
so range of error = +- 0.01

refractive index = 1.52 +- 0.01
percentage error =  0.01/1.52 * 100  = 0.66%