TINV(p,dof)
p: probability
dof: number of degrees of freedom
The survival function is 1 minus the cumulative distribution function.
If p < 0 or p > 1 or dof < 1 this function returns a #NUM! error. The parameterization of this function is different from what is used for, e.g., NORMSINV. This is a common source of mistakes, but necessary for compatibility.
This function is Excel compatible.