 Conditional inference in a location-scale family

For normalized residuals $A_i=(Y_i-\bar{Y})/s$, Fisherian conditional inference uses the conditional distribution of $(\bar{Y},s)$ given the observed $A=a$. For almost every attainable ancillary value, the joint conditional density of $\bar{Y}=m$ and $s=t>0$ is proportional toThe factor $t^{n-2}$ is the radial Jacobian on the $(n-1)$-dimensional centered residual space. After setting $u=(m-\mu )/\sigma$ and $v=t/\sigma$, the conditional density is proportional to $v^{n-2}{\prod }_i{f}_0(u+v{a}_i)$, which is parameter-free. Conditioning on a continuous ancillary uses a regular conditional distribution, rather than division by the probability of a singleton ancillary value.