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# OCR MEI S1 - help watch

1. I don't understand this - question 2 ii)

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2. (Original post by tmifan)
I don't understand this - question 2 ii)

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Hi! I moved this to the Maths forum for you - you're more likely to get an answer here
3. What don't you understand? Have you heard of the binomial distribution previously?
4. There can only be 0,1,2 or 3 women selected from the 3 chosen at random.

You could work out the p(all men (i.e 0 women)) and the p(all women) as this is easier to get your head round/calculate using GCSE level maths. These will be the same of course. Therefore 1- ( P(all men) + p(all women) )/2 will give you the probability of exactly 2 women (or two men) being selected.

For part 2) you now know the probability of selecting 2 women and 1 man, just apply a similar logic as there can be 2 selected on 0,1,2,3 or 4 days although this time it's substantially easier to use the binomial theorum as each days selection is independent of another day. In the first part each selection changes the probability of the next section.

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Updated: May 9, 2016
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