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    on average 1 in 20 members of the population of this country has a particular dna feature. members of the population are selected at random until one is found who has this feature

    (i) Find the probability that the first person to have this feature is not among the first 10 people selected
    (ii) Find the expected number of people selected

    Thank you!
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    What exactly are you struggling with? Please post your working.
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    (Original post by Radioactivedecay)
    What exactly are you struggling with? Please post your working.
    With that question
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    I know the answer, but not sure how to explain the working without saying the answer.
    Someone help?
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    (Original post by Astana)
    With that question
    Part i) multiply the probability that someone doesnt have the feature by itself ten times.
    part ii) this is simply the probability times the sample size.
 
 
 
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