This forum is about wrong numbers in science, politics and the media. It respects good science and good English.
It is impossible to be 95% certain of anything. You are either certain of it, certain that it is untrue, or uncertain.
One can talk of being '95% confident' but a more accurate phrase would be "I estimate the probability of this to be .95 [or 95%]"
They can be 95% certain of the results;but,what if the data used is not accurate?
Most disease studies use data from death certificuts and about 30% of the death certificuts give the wrong cause of death as verified by autopsy.