1, average, statistical term, refers to the quantity representing the trend in a set of data, which means that the sum of all data in a set of data is divided by the number of data in this set. It is an indicator reflecting the trend of data concentration. The key to solve the problem of average application is to determine the "total amount" and the total number of copies corresponding to the total amount.

2. Median is a proper term in statistics, which means a numerical value in a sample, population or probability distribution. It can divide a group of values into equal upper and lower parts.

3. Plural number, or plural number, is one of morphemes. It is used to represent more than one object in a language without even number concept, more than two nouns in a language with even number concept, and non-one object in other languages, including more than one object and nothing.

4. Extreme range, also known as extreme range error or range, is represented by R, which is used to represent the difference between the maximum value and the minimum value of the measurement value of variance in statistical data, that is, the data obtained by subtracting the minimum value from the maximum value.

5. Variance is a measure of dispersion when probability theory and statistical variance measure random variables or a group of data. Variance in probability theory is used to measure the deviation between random variables and their mathematical expectations (that is, the mean value).

Second, the meaning of each number.

1 and the average value can reflect the average level of a group of data; It is an indicator reflecting the trend of data concentration.

2. Mode is the number with the highest frequency in a set of data, that is, mode can reflect most levels of a set of data;

3. The median is the number in the middle of a set of data (when there are odd numbers of data) or the average of the two numbers in the middle (when there are even numbers of data), so the median can reflect the middle position of a set of data.

4. The range is the largest range of mark value change, and it is the simplest indicator to measure mark change. The moving range is one of them. Range can not be used for comparison, the unit is different, variance can be used for comparison, because it is all ratio.

5. Variance or standard deviation is an indicator of the volatility of a group of data, and standard deviation is the arithmetic square root of variance, so variance or standard deviation can judge the stability of a group of data: the greater the variance or standard deviation, the more unstable the data is.

Extended data

The calculation method of each number

1, average

Is to add up all the data and divide it by the number. This is the abbreviation of mathematical average. If it is a geometric average, all the data should be multiplied and then divided by the number. There are other averages. The so-called averages are all mathematical averages, also called averages. All other averages should be noted in particular.

2. Median (median)

The middle value after data sorting. That is, the data is divided into two parts, one part is greater than this value and the other part is less than this value.

3. quantity?

It is the highest frequency number in a row of numbers.

4. Differences

Equal to the sum of squares (average value of each sample)

5. Very poor

R=xmax-xmin (where xmax is the maximum value and xmin is the minimum value)

Baidu Encyclopedia-Average

Baidu encyclopedia-median

Baidu Encyclopedia-WeChat official account

Baidu encyclopedia-extremely poor

Baidu encyclopedia-variance