Note before you start calculating this: There’s a distinction between the “first” and the “second” child made in the article. To avoid the risk of having to calculate all over again, take this into account if you want to compare your results to theirs.
I calculated the probability without knowing this, so that I just counted BG and GB as one scenario, where there’s one girl and one boy. That means that without the Tuesday fact the probability of another boy is 1⁄2, not 1⁄3.
(I ended up at a posterior probability of 2⁄3, by the way.)
Note before you start calculating this: There’s a distinction between the “first” and the “second” child made in the article. To avoid the risk of having to calculate all over again, take this into account if you want to compare your results to theirs.
I calculated the probability without knowing this, so that I just counted BG and GB as one scenario, where there’s one girl and one boy. That means that without the Tuesday fact the probability of another boy is 1⁄2, not 1⁄3.
(I ended up at a posterior probability of 2⁄3, by the way.)