I have a problem which is basically a variation of the coupon problem... I can't get my head around it as I haven't done much stats :uhh:.(adsbygoogle = window.adsbygoogle || []).push({});

I have a sample size of 900, say a pot of 900 balls, each with a unique id. Each week I am going to select a set number of balls randomly from the pot to test them. After testing, the balls go back into the pot. How many balls do I need to test every week so that after 3 years I can be, say, 90% confident that 90% of the sample have been tested in that period.

Any help would be greatly appreciated (especially a solution!!)

Andrew

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# Variation of the coupon problem

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