It's just a very amusing book written by a mathematician about all the ways people in this country fail to understand or properly use math.
I admit that I myself am terrible, almost retarded at doing caluclations and equasions. I can use logic, though. Well enough for me to justly laugh at many excerpts of the books.
Some things were so stupid that anyone should have seen the problem. Like the TV weather man saying that there was a 50% chance of rain on Saturday, and a 50% chance of rain on Sunday, so there was an 100% chance of rain over the weekend.

The point was that even public professionals can get away with such egregious errors, and nobody cares, if they even notice.