stress-free type的意思|示意

But Prof Qureshi added that the type of person who owned a cat was usually already fairly stress-free and at low risk of heart disease.

但库勒什教授说，喜欢养猫的人往往自身就没什么压力，患心脏病的几率也较小。

The application of this method will at least free the estimation from the following two assumptions:1)the life distributions of products at any stress level are of the same or similar type;

应用该方法、至少可以摆脱下述的二个假设：（1）在任一个应力水平上产品的寿命分布都是相同或近似相同类型的；