Measurements of physical quantities are always accompanied by one or another error. It represents the deviation of the measurement results from the true value of the measured value.
Necessary
- -measuring device:
- -calculator.
Instructions
Step 1
Errors can arise as a result of the influence of various factors. Among them, one can single out the imperfection of means or methods of measurement, inaccuracies in their manufacture, non-observance of special conditions during the research.
Step 2
There are several classifications of errors. According to the form of presentation, they can be absolute, relative and reduced. The first is the difference between the calculated and the actual value of the quantity. They are expressed in the units of the phenomenon being measured and are found by the formula: ∆х = hyslchist. The latter are determined by the ratio of absolute errors to the value of the true value of the indicator. The calculation formula is: δ = ∆х / hist. Measured as a percentage or fraction.
Step 3
The reduced error of the measuring device is found as the ratio of ∆х to the normalizing value of хн. Depending on the type of device, it is taken either equal to the measurement limit, or referred to their specific range.
Step 4
According to the conditions of occurrence, there are main and additional ones. If the measurements were carried out under normal conditions, then the first type appears. Deviations due to values outside the normal range are optional. To assess it, the documentation usually sets standards within which the value can change if the measurement conditions are violated.
Step 5
Also, the errors of physical measurements are divided into systematic, random and gross. The former are caused by factors that act upon repeated repetition of measurements. The latter arise from the influence of causes, and are random in nature. A miss is an observation that differs sharply from all others.
Step 6
Depending on the nature of the measured value, different methods of measuring the error can be used. The first of these is the Kornfeld method. It is based on calculating a confidence interval ranging from the minimum to the maximum result. The error in this case will be half the difference between these results: ∆х = (хmax-xmin) / 2. Another way is to calculate the root mean square error.
