Probability

Well technically we don't really know if noble six is dead or not, but it is assumed that he is dead. But to answer your question, (spoiler alert) if you go back and beat the campan on legendary you have to do an extra mission and that is to stay alive but it is impossible so don't try it. Any way he get over taken by some elites and dies. if you want to see what happens here is the link.

See related link below to see what happens

The discovery of the Normal distribution is sometimes attributed to de Moivre, who in 1738 published his results on the coefficients in the binomial expansion of (a + b)n. He calculated results for the mean and spread of the binomial expansion. Although it is now possible to relate his theorem to the Normal approximation of the Binomial Distribution, de Moivre himself, was unable to do so because he was unaware of the the concept of a probability density function.

In 1809, while developing the theory concerning the method of least squares he concluded that the only law which worked was to use the normal law of errors.

A year later Marquis de Laplace proved the Central Limit Theorem. According to this, no matter what the underlying density functions, the means of repeated samples from a population tended towards a nomal distribution. It was also he who calculated the integral of exp(-t2)dt as being sqrt(pi) which allowed the function to be normalised.