However, if you go on the assumption that a member can not be selected twice over a given period, then the odds become additive. I am not sure what all the criteria are for the original question of what the odds are for being selected as a UT Member of the Day.

>Mark,
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>My example was per drawing [per day]. Let's just say your odds are 1 in 1000 of being selected on any 1 day. Over a 20 day period, your odds become additive --
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>1/1000 + 1/1000 .... or 20/1000 or 1 in 50.
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>Adding probabilities is not right: in 2000 days you would get 2 in 1, which is obviously ridiculous. You could either calculate the probability of not being selected: (999/1000)^20 is the probablity of not being selected in 20-day period. So, the being selected at least once: 1-(999/1000)^20 (about 0,20).
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>Auke