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WW4BW
KoldingPosts: **493**Member

Originally posted by Robokapp

Originally posted by MagiknightOriginally posted by RobokappOriginally posted by Magiknight

Once again, regular gambling is a GUARANTEED LOSS for you and win for the industry. It's not a game of chance then. All of the advertisements say the opposite.

Probability...OP did not study it.

If a mother had two children, both girls, what are the odds of third child being a boy ?

a) 0%

b) 12.5%

c) 40%

d) 50%

e) 77.5%

f)100%

g) other

50%. Any other smart questions?

it's actually 40% but for reasons not relevant.

yes. one more.

if there are 37 numbers, one is green, 18 are red and 18 are black, and betting on red or on black and winning doubles your money, what are your chances of winning ?

Couldnt post in the other thread and couldnt quote correctly from it... But I wanted to call bullshit on the 40%... its 51.2 or 52% actually according to what I learned in school and what I could look up in seconds. This is due to the Y chromosomes being faster swimmers. Now men dont live as long as women on average in part due to fact that the Y chromosome is mostly junk dna and doesnt offer alleles to a faulty gene on the X chromosome. I wonder where you pulled 40% from.

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This discussion has been closed.

## Comments

555Memberhttp://chroniclesofthenerds.com/nerdfight/

Y U NO FLIP TABLE?!?!?!

782Member Common782Member CommonHow do you get 60% and 40% just based on statistical probability?

493MemberFrom a minutes of thinking and searching, as opposed to seconds in my first post, I have now come up with the statistical number of 3 girls in a row being 11.6550117%.

But as they say; "there are lies, damned lies, and statistics. So i suppose the numbers can come down to how you look at it.. but is, most definatly, not, in any situation, 50/50. And I suppose that was the point Robokapp was really trying to make.

782Member Common4,818MemberSo you made a new thread because the other one was locked...called it what you did...and then agreed with him

smrt

782Member Common782Member CommonI don't even know what this means.

493MemberHey I just really wanted to know how he came to 40%... and I couldnt ask in the other thread.. besides it was not really on topic. I suppose I could have sent him a private message, to satisfy my curiosity.. But I might as well make sure that the whole "class" can learn.

Besides I only agreed with him as far as the number couldnt possibly be 50%

782Member CommonIt's 51%...

493MemberThis is where it gets fishy. Because depending on how you look at it, it is and it isn't.

The probability of having 3 girls in a row looks like it is somewhere around 11.7% (0.49³)

But in each event there is 51%ish chance of a boy.

I actually thought it was a statistic I had dragged up in my earlier post. But if it had been Im sure the number would have been messier.. Because I am pretty sure there are other factors than this calculation that would come into play in real life.

782Member CommonYou don't take it to the third power because it's an independent event. If it was a dependent events you would use the third power. This is reality. 51% of the human population is male. 49% is female.

493MemberHmm No.

"If a mother had two children, both girls, what are the odds of third child being a boy ?"Clearly they arent independent.782Member CommonA dependent event is effected by the previous event. For example, if you have 2 blue balls and 2 green balls mixed together in a bag. You reach in and grab a ball at random. The next time you grab a ball your chances will be different.

An independent event is not effected by the previous event. For example, flipping a coin. Each time you flip it there is an equal chance of getting heads or tails. Having a boy or girl is NOT effected by the previous child you had.

493MemberAah , had to read up on what it was called in english.. Seems we were both using it incorrectly.

You were using it wrong because it doesnt matter in this case. I was using it wrong because I thought you meant something else.

If it had been a dependent event. It would have been a case of depleting the X cromosomes in the father.. And that doesnt really make any sense.. So yes they are each independent events..

But it is a series of events.. and so you have to compound the probability.

But our disagreement probably comes down to reading the question differently.

I read to mean that I should compound the probabilty of independent events. And you chose to ignore data and look at the singular event.

608Member Uncommon124Member2,861Moderator UncommonTo give feedback on moderation, contact mikeb@mmorpg.com