Chapter 3. Bayes Theorem

There is an error in Figure 3.3. This is the tree diagram representing Eddy's (1982) medical problem. For the branch representing P(Negative | Cancer) the probability should be 0.208, NOT 0.028. Accordingly, the number at the rightmost end of the branch should be 0.0028, NOT 0.00028.

This does not affect the answer to the problem stated in the text, which remains 0.077.

My thanks to Chloe Turner (one of my students) for pointing this out.

Chapter 6: Error in the formula for phi

Page 63 contains a footnote where I give the formula for the phi coefficient. Unfortunately, the denominator mixes up products and sums, so is incorrect. The correct formula should be:

phi = ad - bc / SQRT [(a + b) x (c + d) x (a + c) x (b + d)]

I'm grateful to John van den Bercken for pointing this out.

David

Chapter 1. "Let's do it..."

On page 4, I wrote:

"As Ayton (2000, p.667) put it (in the style of Irving Berlin): 'Birds do it, bees do it, even educated Ph.D.s do it; why not violate normative rules of rationality?'"

In fact, the song alluded to here "Let's do it (Let's fall in love)" was written by Cole Porter, not Irving Berlin! This fact, which I had known for a long time, suddenly popped into my head - apparently at random - about a year after writing the Introduction. I don't know why I got it wrong in the book.

http://en.wikipedia.org/wiki/Cole_Porter