you need
  • - the results of measurements;
  • - Calculator.
First of all, spend a few measuring device of the same size, to be able to calculate the actual value.The more measurements will be carried out, the more accurate the results will be.For example, consider the apple on electronic scales.Let's say you got the results of 0.106, 0.111, 0.098 kg.
Now count the value of the actual (real as real can not be found).To do this, add the results and divide them by the number of measurements, that is, find the arithmetic mean.In the example the actual value will be (0.106 + 0.111 + 0.098) / 3 = 0.105.
To calculate the absolute error of the first measurement subtracted from the actual value: 0,106-0,105 = 0,001.L
ikewise calculate the absolute error of the remaining measurements.Please note that regardless of the result obtained with a minus or plus sign error is always positive (that is, you take the absolute value).
To get the relative error of the first measurement, divide the absolute error in the actual value: 0.001 / 0.105 = 0.0095.Note that the relative error is usually measured as a percentage, so multiply that number by 100%: 0,0095h100% = 0.95%.Likewise, consider the relative error of the remaining measurements.
If the true value is already known, immediately start for the calculation of errors by eliminating the arithmetic mean of the search results.Just subtract from the true significance of the results, and you'll find the absolute error.
then divide the absolute error on the true value and multiplied by 100% - this is the relative error.For example, the number of students 197, but rounded up to 200. In this case, calculate the rounding error: 197-200 = 3, the relative error of 3 / 197h100% = 1.5%.