The relationship between two variables is generally considered strong when their r value is larger than 0.7. The correlation r measures the strength of the linear relationship between two quantitative variables.
ne of the most common ways that we quantify a relationship between two variables is by using the Pearson correlation coefficient, which is a measure of the linear association between two variables. It has a value between -1 and 1 where:
- -1 indicates a perfectly negative linear correlation between two variables
- 0 indicates no linear correlation between two variables
- 1 indicates a perfectly positive linear correlation between two variables
Often denoted as r, this number helps us understand how strong a relationship is between two variables. The further away r is from zero, the stronger the relationship between the two variables.
- Strong positive correlation: When the value of one variable increases, the value of the other variable increases in a similar fashion.
- Strong negative correlation: When the value of one variable increases, the value of the other variable tends to decrease.
