Selection Mechanical

Selection is mechanical.

Mechanical selection is a method used in statistics, where observations are randomly selected from the total mass of data, without taking into account any specific patterns.

The meaning of mechanical selection is that every mth unit of the population is included in the sample. That is, first we determine the entire number of some elements, and then we take a random number of elements from this number, a multiple of this number. This number is called the “power of the sample population.”

Example: Let there be 7 first classes on the list, each class has 5 students, a total of 35 students. It is required to select 5 classes randomly. First of all, let's calculate the “power of the selected sample”: ```md Class | Number of students ------------------------ 1 [1,2,3,4,5] 2 [6,7,8,9,10] 3 [11,12,13,14,15] 4 [16,17,18,19,20] 5 [21,22,23,24,2

Mechanical selection is one of the methods of forming a sample population, in which units of the general population are selected in a certain order. In this case, only those units that meet the given condition are selected.

Mechanical selection is based on the idea that the general population can be represented as a sequence of units arranged in a certain order, for example, alphabetically, by time of appearance, or by some other pattern. Further, from this sequence certain intervals are selected that are multiples of a given number, for example, every fifth or tenth unit. Thus, with mechanical selection, we obtain a sample that represents a part of the general population and reflects its main characteristics.

Mechanical selection has its advantages and disadvantages. The advantages include simplicity and ease of use, as well as the ability to accurately determine the sample size. The disadvantage is that the result obtained may be distorted if there are heterogeneities in the population or if the population units are unevenly distributed.

One example of the use of mechanical selection is the selection of telephone numbers in a telephone book. Here, each page of the book can be taken as an interval, and each entry on the page can be selected as a sampling unit. This produces a sample that is a random sample from a list of telephone numbers.

Another example of the use of mechanical selection would be the selection of students in an exam. Here, each group of students can be taken as a sampling unit and each student can be selected randomly. This provides insight into the knowledge and abilities of all students taking the exam.

Thus, mechanical selection is a simple and convenient method for forming a sample population. It allows obtaining a random sample, but requires caution in its use, especially when the population has heterogeneity.