One thing though - I am looking at chapter 6 page 180. The numbers substituted into the equation don't match with the values in the tree diagram. Have I missed something?
On page 182 the more formal equation which gives the same result is for P(L|+) which is what I expect.
I've noticed the same questions:
p174 - isn't 9% of 90 more like 8 people?
p180 - The arrow pointing to "The number of people who have it" blank should really say something like "90% of people who actually have the flu test positive for it", and then on the "The number of people who don't have it", the arrow there should say something like "9% of people who don't have it, test positive for it". I think in the equation, we need to substitute 'positive' for 'negative', since we are looking for P(L|+)
...but I'm not a data analyst, so some confirmation would be appreciated :-)