What is the best correlation coefficient for a school to investigate students' satisfaction with the canteen?
Pearman rank sum test correlation coefficient. Spearman rank sum test correlation coefficient is especially suitable for hierarchical data or nonlinear data, while canteen satisfaction score is hierarchical (such as very dissatisfied, dissatisfied, general, satisfied, very satisfied) and there is a nonlinear relationship, so it is best to use pearman rank sum test correlation coefficient.