Not counting the setting of hardware for mining.. but considering the hypothetical statistics of an example here..
I don’t know in very detail what the mining difficulty is, but we will take an example of me running a pool with 100TH/s.. taking TH as an example I don’t know much about the hardware at the mining nor the power it provides.. but I am learning slowly.
So there are pools that provides a lot of hashing power, some provide a lot compared to others, sometimes even the pools that provides 10 times less the hashrate compared to other pools are able to mine a block..
Does it depends on luck too?, how does actually the bitcoin network network decides who mines the block, what’s the catch..
Everything you need to know about how a miner & pool work together can be found
here at Kano's site and all the technical details
right under that here.