Top priority of dry goods: common indicators and terms in data analysis!

Data interpretation is the basic skill of data analysts , If you can't fully understand all kinds of indicators and terms in data analysis , Data analysis will be difficult .

For data analysts , Understanding the commonly used analysis indicators and terms is the premise of good data interpretation . below , Let's learn about common indicators and terms .

 1. The average  

The average is the most commonly used statistic in Statistics , Including the arithmetic mean 、 Geometric mean 、 Harmonic mean 、 Weighted average 、 Index average, etc . Usually, the average we say in life refers to the arithmetic average .

Arithmetic mean means , In a set of data, the sum of all data is divided by the number of this set of data , It is an indicator reflecting the trend of data set .

 2. Absolute and relative numbers  

Absolute numbers are also commonly used indicators in data analysis . The commonly used total indicator in statistics is absolute , It reflects the overall objective phenomenon at a certain time 、 Total size under site conditions 、 Comprehensive indicators of the overall level . For example, the total grain output within a certain range 、 Total industrial and agricultural output value 、 Number of enterprise units .

Relative number is also called relative index , It is the ratio calculated by two related indicators , It can quantitatively reflect the comparative relationship between two interrelated phenomena . The basic calculation formula of relative number is ：

In the formula above , The base value is the index value used as the comparison standard , Abbreviated as cardinality ; The comparison value is the index value used to compare with the base , Ratio for short . Relative numbers are usually in multiples 、 Percentage, etc , It reflects the degree of quantitative connection between objective phenomena .

When using relative numbers, we need to pay attention to the comparability between indicators , At the same time, it should follow the total amount index ( Absolute number ) Use a combination of .

 3. Percentages and percentages  

Percentage is an expression of proportion 、 Method of ratio or fraction value . It is one of the relative numbers , Also called percentage or percentage . It is not usually written in the form of fractions , Instead, use symbols “%” To express , Such as 5%、40%、80%. Because the denominator of percentage is 100, So it's all 1% As a unit of measure .

Percentage point refers to the relative index expressed in the form of percentage in different periods ( Example index 、 Speed 、 Composition, etc ) The range of change in .

In actual use, we must pay attention to distinguish between percentage and percentage , For example, the conversion rate of a commodity this month is 10%, The conversion rate last month was 8%, It can be said that the conversion rate of this commodity this month has increased by two percentage points compared with last month , Not 2% or 2%.

 4. Proportion and ratio  

Proportion is the proportion of the number of each part in a total , Used to reflect the overall composition or structure . for example A The company has 500 Employees , Male employees 260 name , Female employees 240 name , Then the proportion of male employees is 260:500, The proportion of female employees is 240:500.

Ratio refers to the ratio between different categories of data in a sample or population , Because the ratio is not a comparative relationship between the part and the whole , So the ratio may be greater than 1. Just like the example mentioned above ,A The company has male employees 260 people , Female employees 240 people , Then the ratio of male employees to female employees is 260:240.

 5. Frequency and frequency  

Frequency is also called “ frequency ”, It refers to the number representing a certain characteristic in the variable value ( Flag value ) Number of occurrences , Frequency can be represented by table or graph . such as A Company has 500 Employees , Among them is 260 Male employees ,240 Female employees , Then the frequency of male employees is 260, The frequency of female employees is 240.

Frequency refers to the ratio of the number of categories in each group to the total number , It indicates the frequency of a category in the overall . frequency The rate is generally expressed as a percentage , Add the frequencies of all groups to equal 100%.

Or to A Take the employees of the company as an example ,260 Male employees are 500 The frequency of employees is 52%, namely (260÷500)×100%; and 240 Female employees are 500 The frequency of employees is 48%, namely (240÷500)×100%.

 6. Multiples and multiples  

A multiple is the quotient of one number divided by another , such as A÷B=C, It can be said that A yes B Of C times . Multiples are generally used to indicate the increase or increase in quantity , It is not suitable to indicate a decrease or decline in quantity .

Fan refers to the original number 2 Of n Power , For example, the company's profit this year has doubled over last year , It means that the profit this year is twice that of last year (2 Of 1 Power ), This year's profit quadrupled that of last year , This year's profit is last year's 4 times (2 Of 2 Power ).

 7. Year on year and month on month  

Year on year refers to the ratio obtained by comparing with the data in the historical period , It mainly reflects the relativity of the development of things . for example A company Q1 Sales are up year on year 35%, It means that the sales in the first quarter of this year increased compared with that in the first quarter of last year 35%, This is the year-on-year .

The month on month ratio refers to the value obtained by comparing with the data of the previous statistical period , It is mainly used to reflect the development of things phase by phase . for example A company Q2 Sales are up month on month 20%, Means the company Q2 Sales ratio Q1 Our sales have increased 20%.