Quote:
Originally Posted by tomwed
US population 300 million
lets say if 1 out of 10 are left handed and there are twice as many left handed men
30 million = 20 million men and 10 million women
56% of 18 yr old or older Americans are married
160 million= 80 million men and 80 million women
16 million married people are left handed
11 million men 5 million women
therefore the odds are 1 out of 4,389 that both partners are left handed
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I am a statistician and the question is not that difficult.
The assumptions that you made are:
1 in 10 married people are lefthanded
Twice as many married men are lefthanded than married women
In order to meet those two assumptions, the odds of a married man being lefthanded would be 2/15 and a married woman being left handed 1/15. (Taken together that gives you 3 out of 30 married people being lefthanded, which is the same as 1 out of 10.)
So, if a random selection of one male and one female were made, the probability that they were both lefthanded would be 2/15 times 1/15, which is 2/225, or 1 out of 112.5.