Correaltion和迴歸分析

Question

我應該如何分析四個序數（0,1,2,3）和各種範圍的連續值之間的相關性？散點圖看起來像一個4個平行的水平點。

Answer 1

您可以運行Spearman等級相關性測試。使用R，

require(pspearman) 
x <- c(rep("a", 5), rep("b", 5), rep("c", 5), rep("d", 5)) 
x <- factor(x, levels=c("a", "b", "c", "d"), ordered=T) 
y <- 1:20 

spearman.test(x, y) 

    Spearman's rank correlation rho 

data: x and y 
S = 40.6203, p-value = 6.566e-06 
alternative hypothesis: true rho is not equal to 0 
sample estimates: 
     rho 
0.9694584 

Warning message: 
In spearman.test(x, y) : Cannot compute exact p-values with ties 

非顯著相關

set.seed(123) 
y2 <- rnorm(20) 
spearman.test(x, y2) 

Spearman's rank correlation rho 

data: x and y2 
S = 1144.329, p-value = 0.5558 
alternative hypothesis: true rho is not equal to 0 
sample estimates: 
    rho 
0.139602 

Warning message: 
In spearman.test(x, y2) : Cannot compute exact p-values with ties