First off let me say I love math, I love probabilities, quizzes, IQ tests, ... This doesn't mean I'm great at it :)
To help improve this, I usually download math related apps on my mobile phone to keep me entertained on the train. One of these apps contains "probability puzzles". One of the easy puzzles states the following:
Suppose babies are boys with probability 0.51, girls with probability 0.49, and births are independent.
If you have two children, what's the probability they're both girls?
This seemed straight forward to me.
- 0 girls = 0.255
- 1 girl = 0.49
- 2 girls = 0.245
But the puzzle indicates this as wrong. Am I missing something? The only thing I can't quite set into context is the following sentence from the question:
and births are independent
What does this actually mean? (not a native English speaker).