When n ≥ 30 formula 

used to find the critical values for the rank correlation coefficient. For example, if n = 40 and α = 0.05 for a two-tailed test,

Hence, any r_s greater than or equal to + 0.314 or less than or equal to - 0.314 is significant.

For Exercises find the critical r value for each (assume that the test is two-tailed).

n = 60, α = 0.10

r = Iz Vn-1 can be