If there is a large group of small miners (100 H/s), which together have a high rate (10 KH/s), compared to a single larger miner having the same 10 KH/s Do they have same possibility of mine a block? or, because of their small individual strength (100 H/s), although together they have a lot of force, they will not be able to mine a block as easily as the big single miner? Thanks :)
Assuming the total hashrate is the same, both the group of small miners and the large miner have the same probability of finding a block.
That's assuming that the small miner mine through a pool where they share their hashes. Otherwise group of small miners will be at a slight disadvantage due to network latency.