For example, if I ask you to flip a coin 2 times and tell you I'll only pay you if you flip a tails, a lot of people are going to have 2 tails, a lot of people would have 2 heads.  This would be 2 extremely different results (in terms here, some people would be paid 0, some people would be paid 200% of what they expected).  Now, if I tell you to flip it 100 times each, you'll notice some people still have lower than average numbers (maybe 30 tails), some have higher than average (70 tails), some have just about correct (45-55).  Over a long enough time (number of flips here), everyone will come very close to 50/50 (on average).  People with faster miners just flip coins faster, people on CPUs flip coins slower.