This article discusses the essence of random errors, the results of which are subordinate and determined on the basis of the law of normal distribution. At the same time, the main points of calculating the mathematical expressions of the distribution law of a
random variable are studied.
It is also indicated that сconsidering distribution function, it is possible to evaluate any characteristic of a random variable and the possible intervals of its value, and the advantage of this method since the calculation results are 95% of the probability of the
outcome