  In complex systems, responses to small perturbations are too diverse to
predict how much they would be definitely, and then such diverse responses can
be predicted in a probabilistic way. Here we study such a problem in scale-free
networks, for example, the diameter changes by the deletion of each node for
various in silico and real world scale-free networks. We find that the diameter
changes are indeed diverse and exhibit an algebraic decay with an exponent
\zeta asymptotically. Interestingly, the exponent \zeta is robust as \zeta
\simeq 2.2(1) for most scale-free networks, insensitive to the degree exponents
\gamma as long as 2 < \gamma \le 3. However, there is another type with \zeta
\simeq 1.7(1) and its examples include the Internet and its related in silico
model.
