When $H _ { 0 } : \rho = 0$ Is True, the Test Statistic

Short Answer

When $H _ { 0 } : \rho = 0$ is true, the test statistic $T = R \sqrt { n - 2 } / \sqrt { 1 - R ^ { 2 } }$ has a t distribution with __________ degrees of Freedom, where n is the sample size.