Is the ranking method accurate?

What are line difference method and rank method?

What are line difference method and ranking method?

1, line difference method

Line difference method, also known as standard deviation method, refers to comparing two groups of data, calculating their average values, and then calculating the difference between the two groups of average values, that is, the line difference between the two groups of data. This is a method to measure the difference between the two groups of data. The advantage of line difference method is simple and easy to calculate. When the measurement units of the two groups of data are the same or the values are close, the line difference method is suitable for comparison.

For example, the math scores of a class in the final exam are as follows:

Class A: 72, 80, 68, 85, 76, 70, 90, 88, 75, 80.

Class B: 78, 82, 70, 80, 84, 75, 92, 85, 80, 90.

Now, in order to compare the average values of these two classes, we can use the line difference method to get the following results:

Grade A average: 76.4

Class b average: 8 1.4.

Class b is higher than class a: 8 1.4-76.4 = 5.

Through the comparison results of line difference method, it can be concluded that the average value of class B is 5 points higher than that of class A. It should be noted that line difference method can only express the differences of data, but cannot reflect the specific characteristics of a certain group of data.

2. Ranking method

Rank method, also known as sorting method, refers to combining two groups of data to be compared into one group, then sorting by size, and then recording the position of each group of data in the arrangement, which is called sorting. Ranking method is widely used in some fields, such as the ranking in sports competitions and the comparison of market share of enterprises. The advantage of ranking method lies in its objectivity.

For example, the sales of two e-commerce platforms are as follows:

Platform A: 1 10,000,1.20,800,900,000,1.50,800,000.

Platform B: 900,000, 165438+ 10,000,700,850,000,1.35,000,800,000.

Now, if you want to compare the sales of the two platforms, you can use the ranking method to get the following results:

The total sales of platforms A and B are: 6,543.8+0,000, 6,543.8+0.2 million, 800,000, 900,000, 6,543.8+0.5 million, 800,000, 900,000, 654.38+0.38, 700,000, 850,000 and 6,543.38+0.38 respectively.

The total sales amount is 700,000, 800,000 (ranked 3rd), 800,000 (ranked 7th), 850,000 (ranked 9th), 900,000 (ranked 4th), 900,000 (ranked 8th), 6,543.38+0,000 (ranked 654.38+0) and 6,543.38+respectively.

After the merger, the sales rankings of Platform A are 1, 2, 3, 4, 5 and 6 respectively.

After the merger, the sales rankings of Platform B are: 3, 5, 7, 9, 8 and 6 respectively.

Through the comparison results of ranking method, it can be concluded that the sales of platform A are higher.

Line difference method and sorting method are commonly used in statistics to compare the size of grouped data, and their differences are mainly manifested in the following aspects:

1, the principle is different

The line difference method judges the differences between data by comparing the differences of average data, and only considers the size of data, regardless of the location of data. Sorting method is to judge the difference between data by comparing the sorting of each group of data in data set, which not only considers the size of data, but also considers the location of data.

2. Different data processing methods.

In the line difference method, before comparing the two groups of data, it is necessary to calculate their average and line difference, and then compare the differences between the two groups of data with line difference. In the sorting method, it is necessary to merge two groups of data into one group, then sort them, compare the positions occupied by each group of data according to the sorting, and finally calculate the difference of sorting.

3. Different usage scenarios.

The line difference method is suitable for the case that the measurement units of the two groups of data are the same or close, while the sorting method is suitable for the case that the measurement units of different data are inconsistent, such as the sorting of various sports competitions. Because the scores and achievements of various sports categories are different and cannot be directly compared, ranking method is more common.

4. The measurement results have different meanings.

The line difference method compares the average difference between two groups of data and cannot reflect the specific characteristics of a group of data, while the sorting method can accurately reflect the size relationship of each group of data in the population and show the sorting. In practical application, the two methods may get different results, so it is necessary to choose the appropriate method according to the specific situation.

To sum up, although the line difference method and sorting method are both methods to compare the size of grouped data, they are different in principle, data processing mode, usage scenarios, meaning of measurement results and so on, and need to be selected and applied according to specific conditions.