\begin{equation*}
    Z_{M}(g)(t)=\frac{1}{\sqrt{M}} \sum_{i=1}^{n}\sum_{j=1}^{N_{i}}\left[\psi_{n}(Y_{ij}, T_{ij}; g) K_{T_{ij}}(t)-E\left\{\psi_{n}(Y, T; g) K_{T}(t)\right\}\right].
\end{equation*}
