As they hike, the boys in the troop keep getting spread out further and further. It seems Alex discovered the true meaning of "dependent events" in relation to "statistical fluctuations" by fluke! This analogy between a single file hike through the mountains and a manufacturing plant, makes Alex realize the difficulty of making up the downside of the fluctuations following "dependent events". The last event must always catch up everything to average out, which rarely ever happens.
Could you please help me to understand this paragraph by easy words?