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Memoryless property for the geometric distribution

Thabo Motaung

Keen member
Good day

For the example in the notes that displays the memoryless property where a woman has two boys and a girl, the probability of a success is 0.5, and they want to calculate the probability that her next two children are girls. Since here x = 2, I wanted to know what n is because it seems as though that n = 2 here so that x + n = 4 so that the maths works out but exactly why that is the case I cannot understand. I would have assumed n = 3 since we have that X is the rv that she bears 2 girls and n is the number of trials that have passed without seeing that success(i.e of not having two children which are girls) which works out to be 3.

Thank you
 
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