Problem with your book

[UATrewqaz]

Edit: I seriously think the OP is a troll after reading most of the thread.

If you flip a fair coin and it lands tail 19 times in a row

on the 20th flip the odds of it being heads are 50%

no more, no less.

The reason long term probabilities work is not because each tail makes an upcoming heads "more likely" but because a long term span will also eventually include a period of time where it comes 19 heads in a row.