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The Pearson correlation coefficient varies from -1 to +1,
When r>0 indicates that the two variables are positively correlated, that is, the greater the value of one variable, the greater the value of the other variable;
r<0 indicates that two variables are negatively correlated, that is, the larger the value of one variable, the smaller the value of the other variable.
The greater the absolute value of r, the stronger the correlation between the two variables.
If r=0, it indicates that the two variables are not linearly correlated, but there may be correlations in other ways (such as curved lines).
Extended information:
(1) Generally believed that:
- When |r|≥0.8, it can be considered that the two variables are highly correlated;
- 0.5≤|r|<0.8, it can be considered that the two variables are moderately correlated;
- 0.3≤|r|<0.5, it can be considered that the two variables have a low degree of correlation;
- |r|<0.3, it can be considered that the two variables are basically irrelevant.
(2) Some think:
- When |r|≥0.8, it can be considered that the two variables are extremely highly correlated;
- 0.6≤|r|<0.8, it can be considered that the two variables are highly correlated;
- 0.4≤|r|<0.6, it can be considered that the two variables are moderately correlated;
- 0.2≤|r|<0.4, it can be considered that the two variables are lowly correlated;
- |r|<0.2, it can be considered that the two variables are basically irrelevant.
(3) It is also believed that:
- When |r|≥0.7, it can be considered that there is a strong correlation between the two variables;
- 0.4≤|r|<0.7, it can be considered that the two variables are moderately correlated;
- 0.2≤|r|<0.4, it can be considered that the two variables are weakly correlated;
- |r|<0.2, it can be considered that the two variables are extremely weakly correlated or uncorrelated.