Yes, this is right.

The case of Mertens' conjecture is interesting in that surface level heuristic considerations suggest that it's not true. In particular, it violates the heuristic that I described here.

Roughly speaking, the function "the difference between the number of natural numbers up to k with an odd number of prime factors and the number of natural numbers up to k with an even number of prime factors" is supposed to be normally distributed with standard deviation 'square root of k,' and Merten's conjecture predicts a truncated normal distribution.