This claim is repeated often, but numerous attempts have failed to demonstrate that this is generally the case in practice (there have been a couple of studies showing an effect in very specific circumstances). Static types might indeed assist with correctness, but they are not the only thing that does, and in some situations they could come at the expense of others. I.e., even if types were shown to significantly help with correctness, it does not follow that if you want correctness your best course would be to add types.
Given empirical studies, the current working hypothesis should be that if static types do have a positive effect on correctness, it is a small one (if it were big, detecting it would have been easy).
Note that Matlab, the workhorse of scientific computing for a few decades now, is even less typed than Julia. That's not to say that Julia doesn't suffer from too many correctness issues (I have no knowledge on the matter), but even if it does, there is little support for the claim that typing is the most effective solution.