Original sentence: It says that the probability that a given, randomly chosen number  is prime is inversely proportional to its number of digits, or to the logarithm of n.The distribution of primes, that is to say, the statistical behaviour of primes in the large, is described by the prime number theorem, proven at the end of the 19th century
Edited sentence: However, the distribution of primes, that is to say, the statistical behaviour of primes in the large, can be modelled.The first result in that direction is the prime number theorem, proven at the end of the 19th century, which says that the probability that a given, randomly chosen number  is prime is inversely proportional to its number of digits, or to the logarithm of n.There is no known useful formula that sets apart all of the prime numbers from composites