Judging the accuracy of coinwarz's solo mining calculator

I'm trying to determine when to solo mine an alt coin - obviously I can't solo mine BTC. :)

The calculator on coinwarz states:

Days to generate one block mining solo: 33.89 Day(s) (can vary greatly depending on your luck)

So the question is what does this truly mean? I've solo mined before but only on such low diff coins that I wasn't concerned.

But at 30 days or so. Yikes, there is a concern.

When you flip a coin the expected time to get a head (or tail) is 2 flips (generally speaking).

More precisely you have a 50% chance of getting a head in one flip; 75% chance in two; 87.5% chance in three ... and so on.

So what does Coinwarz mean when they say 33.89 days? Is this the "two flips" sort of answer or is it something else?

My z-nomp pool, for example, gives a completely different answer. It says that my "luck" is 12 days.

http://ift.tt/2jAene8

Bitcoin Magician