]> $$1-P\left(t;\nu ;\delta \right)=\frac{1}{2}\sum _{i=0}^{\infty }\left(P_i{I}_y\left(\frac{\nu }{2},i+\frac{1}{2}\right)+\frac{\delta }{\sqrt{2}}{Q}_i{I}_y\left(\frac{\nu }{2},i+1\right)\right);y=1-x=\frac{\nu }{\nu +t^2}$$