Errors of measurement-
generally it is seen the measured value of a quantity is different from its actual value . this difference in the measured value and and the true value of a quantity is called error of measurement.
Errors of measurement can be divided into following types-
Systematic errors -Those errors whose causes are known and it can be corrected ( or , can be minimised). Like Instrumental errors, personal errors ,Error due to imperfection and errors due to external causes.
Random errors-These errors may arise due to large variety of factors . some time it is also called ‘ chance error’ . random errors can be minimised by repeating the observation.
Gross errors– These errors arises due to carelessness of the observer during the measurement of the values.
Absolute errors– Absolute errors in the measurement is the difference between true value and measured value of the quantities . The absolute errors sometime may be positive and sometime negative .
Mean absolute error-It is the arithmetic mean of magnitudes of absolute errors.
Relative errors /Fractional errors-It is the ratio of mean absolute errors to the mean value or true value of the quantities measured.
Permissible errors-It is the errors which arises due to limitations on the measuring abilities of various instruments use in the experiment.
Accuracy– It is the extent to which a measurement approaches the true value of the quantities measured.
Precision– It describes the limitations of the measuring instruments . It is the degree of correctness of a measurement.