Fig. 1

The surface plot of the joint PDF of \(T_{1} ,\;T_{2}\) with different values of \(\theta_{0} ,\;\theta_{1} ,\;\theta_{2}\) when \(\lambda = 2\). a \(\theta_{0} = \theta_{1} = \theta_{2} = 1\), b \(\theta_{0} = 0.5,\theta_{1} = \theta_{2} = 0.8\), c \(\theta_{0} = 0,\theta_{1} = \theta_{2} = 0.4\), d \(\theta_{0} = \theta_{1} = \theta_{2} = 0.2\)