I heard about the 1054 supernova that was visible with the naked eye.
Of course, these events happen at random. But just like with radioactive decay, it must be possible to determine statistics on these kinds of events.
The total supernova rate in our galaxy is estimated to be between 2 and 12 per century
but this doesn't indicate anything about their visibility from Earth. In fact, quite a few supernovas in the Milky Way probably go unnoticed, so the rate of visible supernovas is likely lower.
In addition, type Ia supernovas can outshine the galaxy they are in, so if one occurred in Andromeda or a Magellanic Cloud, it might be visible. So there possibly could be more visible supernovas than there are supernovas in just our Galaxy.
What is the average time between two supernovas that are visible with the naked eye?