The readings of a length come out to be 2.63 m , 2.56 m , 2.42 m , 2.71 m and 2.80 m . Calculate the absolute errors and relative errors or percentage errors.

Explanation

The mean value of length `L= ((2.63 + 2.56 + 2.42 + 2.71 + 2.80)m)/(5)`
`=(13.12)/(5)m= 2.624m= 2.62m`
As the lengths are measured to a resolution of 0.01m, all lengths are given to the second place of decimal, it is proper to round off this mean length also to the second place of decimal.
In the first measurement
Error `= Delta x_(1)= 2.63m- 2.62m = +0.01m`
Absolute error = 0.01m
Relative error= 0.01/2.62 = 0.0038
Percentage error= relative error `xx 100= 0.38%`
In the second measurement
Error =`Delta x_(2)= 2.56m - 2.62m= -0.06m`
Absolute error= 0.06m
Relative error = 0.06/2.62 = 0.023
Percentage error= relative error = `xx 100= 2.3%`
In the third measurement
Error = `Delta x_(3)= 2.42m- 2.62m= -0.2m`
Absolute error = 0.2m
Relative error =0.2/2.62= 0.076
Percentage error= relative error `xx 100= 7.6%`
In the fourth measurement
Error = `Delta x_(4)= 2.71 m- 2.62m= +0.09m`
Absolute error = 0.09m
Relative error= 0.09/2.62 = 0.034
Percentage error= relative error `xx 100= 3.4%`
In the fifth measurement
Error = `Delta x_(5)= 2.80m- 2.62m= +0.18m`
Absolute error= 0.18m
Relative error = 0.18/2.62= 0.068
Percentage error= relative error `xx 100 = 6.8%`
Mean or final absolute error = `(Sigma_(1)^(5) |Delta x_(i)|)/(5)`
`=((0.01 + 0.06 + 0.20 + 0.09 + 0.18)m)/(5)`
= 0.54m/5= 0.108 m= 0.11m
This means that the length is `(2.62 +- 0.11m)`
i.e., it lies between `(2.62 + 0.11) and (2.62 -0.11m)`
i.e., between 2.73m and 2.51m