Based on the mathematical theory of probability, Law of Statistical Regularity states that if a sample is taken at random from a population, it is likely to possess the characteristics as that of the population. A sample selected in this manner would be representative of the population. If this condition is satisfied, it is possible for one to depict fairly accurately the characteristics of the population by studying only a part of it.
The Law of Inertia of Large Numbers‘ is a corollary of the law of statistical regularity. It states that, other things being equal, larger the size of sample, more accurate the results are likely to be. This is because when large numbers are considered, the variations in the component parts tend to balance each other and, therefore, the variation in the aggregate is insignificant.