Average = total quantity ÷ total number of copies.
2. Median, also called median, is a proper noun in statistics, and it is a number in the middle of a set of data arranged in order.
Arrange the data in order of size, and the middle number of the data is the median.
3. The mode refers to the numerical value with obvious concentration of trend points in statistical distribution, which represents the approximate level of data. Represented by m.
The mode does not need to be calculated, and the value with the highest frequency in a set of data is the mode.
Extended data
Average, median and mode are all statistics that describe the average level of data, and each has its own characteristics. Everyone is familiar with the average, the median describes the middle level of a set of data, and the mode describes the situation with the highest frequency in a set of data.
An obvious advantage of the average value is that it can make use of the characteristics of all data and is relatively easy to calculate. In addition, in mathematics, the average value is a statistic that minimizes the sum of squares of errors, that is to say, using the average value to represent data can minimize the secondary loss.
Therefore, the average value is a commonly used statistic in mathematics. However, the average also has some disadvantages, precisely because it uses all the information of data, and the average is easily influenced by extreme data.
For example, in a unit, if the salary of the manager and deputy manager is particularly high, the average salary of all members of the unit will be high, but in fact, the average salary of everyone except the manager and deputy manager is not very high. At this time, median and mode may be more reasonable statistical data to describe the average wage level of all personnel in this unit.
The characteristics of median and mode statistics are that they can avoid extreme data, but the disadvantage is that they do not make full use of the information reflected by the data. Because each statistic has its own characteristics, we need to choose the appropriate statistic according to the actual problem.
Of course, when extreme data appear, it is not necessary to use the median. Generally, there is a statistical method, that is, the data is not from this population, so the data is removed. For example, the well-known diving competition results, why should we remove a highest score and a lowest score? You don't think these two scores come from this whole and can't represent the judgment. So after removing it, we will average the remaining data.
It should be pointed out that most of the data we process are symmetric data, and the data conform to or approximate normal distribution. At this time, the mean (average), median and mode are all the same.
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