[R] cor.test() -> p-values may be incorrect due to tie

[Jan Verbesselt]

Hi R specialists,

When testing the association between two time series the cor.test gives
the following message...-> p-values may be incorrect due to tie

What does it mean? (it is not described in the help)

Thankx,
Jan


>  cor.test(Origi[,1],Origi[,2], alternative = c("two.sided"),method =
c("spearman"), conf.level = 0.95)

        Spearman's rank correlation rho

data:  Origi[, 1] and Origi[, 2] 
S = 101457, p-value = < 2.2e-16
alternative hypothesis: true rho is not equal to 0 
sample estimates:
      rho 
0.8938577 

Warning message: 
p-values may be incorrect due to ties in: cor.test.default(Origi[, 1],
Origi[, 2], alternative = c("two.sided"),