This relationship is consistent for all the t. The basic Gamma degradation process, the bootstrap-t methods generally produce confidence intervals having coverage probability larger than the nominal value. In other words, the bootstrap-t methods are conservative here. On the contrary, the coverage probability of the confidence interval calculated by BCa is slightly smaller than the desired level, i.e. the BCa method is anti-conservative in this application. The bootstrap-t intervals tend to be unstable and have wider confidence intervals than both percentile and BCa intervals, which can be seen clearly. But it is still worthwhile to analyze and compare its intervals with those of others.