In: Statistics and Probability
This is a false statement. If the sample correlation between two random variables is small in magnitude (say 0.1), it does not necessarily imply that the test for the significance of the correlation will have a large p-value (> 0.05)
A small sample correlation between two random variables for large sample size may have low p-value for the test for the significance of the correlation
For example, let's say we get the sample correlation between two random variables as 0.1 from 1000 observations (n = 1000).
Test statistic, t = = 3.18
Degree of freedom = n-2 = 1000 - 2 = 998
For two-tail test, (Ha: 0) ,
p-value = 2 * p(t > 3.18) = 0.0015
Thus, we have get low p-value (< 0.05) for small sample correlation between two random variables.