I heard all 'interpretations' of quantum mechanics give exactly the same answer to every measurement so they are all equally correct.
It is common for physicists to say that the interpretations all give the same results, but they are wrong.
The interpretations fit into a couple of different categories. One interpretation takes the equations of motion of quantum mechanics, e.g. - the Schrodinger equation or Heisenberg equations of motion. That interpretation is called the many worlds interpretation of quantum mechanics (MWI). That term is used because it predicts the existence of structures each of which approximately resembles the universe as described by classical physics:
The MWI is experimentally testable, false claims to the contrary notwithstanding:
Some other interpretations are distinct physical theories that make different predictions and might in principle be distinguished from quantum mechanics by experiment, such as the grw collapse theory and the pilot wave theory:
The other interpretations, the Copenhagen interpretation (CI) and statistical interpretation (SI), are just bad philosophy dressed up as physics.
The CI claims that quantum mechanics should be used to calculate some stuff but is incomprehensible so you have to describe other stuff in terms of classical physics. But this position is deemed by fiat somehow to be equivalent to quantum mechanics, i.e. - the MWI. However, since any experimental result is an explanation of what happened at a particular place and time, not just some figures arbitrarily written on a page, the claim that quantum mechanics is incomprehensible rules out making any experimental predictions using the theory. If it is not possible to explain what events are taking place in an experiment, then it is not possible to tell whether the experiment is working. As such, the CI makes no experimental predictions.
The SI claims that quantum mechanics just makes predictions about probabilities. In reality, the quantities that are commonly described as probabilities only obey the rules of probability in some specific situations and break those rules in many experiments:
So the SI appears just to be contradicted by reality. The SI's adovcates like to claim science is just about predicting experimental results. This strategy is not viable since experimental results have to be explanations not just stuff some guy wrote down for reasons explained previously.