Relative error due to a single bit-flip in floating-point arithmetic

We consider the error due to a single bit-flip in a floating point number. We assume IEEE 754 double precision arithmetic, which encodes binary floating point numbers in a 64-bit word. We assume that the bit-flip happens randomly so it has equi-probability (1/64) to hit any of the 64 bits. Since we want to mitigate the assumption on our initial floating-point number, we assume that it is uniformly picked among all normalized number. With this framework, we can summarize our findings as follows. The probability for a single bit flip to cause a relative error less than 10^-11 in a normalized floating-point number is above 25%; The probability for a single bit flip to cause a relative error less than 10^-6 in a normalized floating-point number is above 50%; Etc.