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How much does the correlation coefficient matter?
Correlation coefficient is the first statistical index designed by statistician karl pearson, and it is the quantity to study the linear correlation between variables. Generally, it is represented by the letter R. Because of different research objects, there are many definitions of correlation coefficient, and Pearson correlation coefficient is the most commonly used one.

The absolute value of correlation coefficient r is generally above 0.8, and it is considered that A and B have a strong correlation. Between 0.3 and 0.8, it can be considered that there is weak correlation. Below 0.3, there is no correlation.

Extended data

Correlation table and graph can reflect the relationship between two variables and their correlation direction, but they can't accurately show the degree of correlation between two variables. Correlation coefficient is a statistical index reflecting the close correlation between variables. The correlation coefficient is calculated according to the product-difference method, which is also based on the deviation between two variables and their respective average values, and the correlation degree between the two variables is reflected by multiplying the two deviations; The linear single correlation coefficient is studied emphatically.

It should be noted that Pearson correlation coefficient is not the only correlation coefficient, but the most common correlation coefficient. The following explanation is aimed at Pearson correlation coefficient.

According to the different characteristics of related phenomena, the names of their statistical indicators are also different. For example, the statistical index reflecting the linear correlation between two variables is called correlation coefficient (the square of correlation coefficient is called judgment coefficient); The statistical indexes reflecting the curve correlation between two variables are called nonlinear correlation coefficient and nonlinear judgment coefficient. The statistical indexes reflecting multivariate linear correlation are called complex correlation coefficient and complex judgment coefficient.

References:

Baidu encyclopedia correlation coefficient