A couple with eight daughters decides to have one more baby, because they think

this time they are sure to have boy! Is this reasoning accurate?

2 answers

nope - same old 50-50 chance.

Although, given their previous children, I ct the chances are high that they'll have another daughter. There may be something other than random chance at work here.
http://drdavespsychologypage.homestead.com/Odds__Figuring.pdf