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# (MEI S1 - Probability) Stuck on exercise question watch

1. Hi all,

I've uploaded my work so far

I've got work out the probability that at least two of the witnesses select the accused. I know I could do this by working it all out manually, was just wondering if there was a quicker way to do it?

Many thanks,
Robin
2. Since the probability for each witness selecting an accused is the same across all 3 witnesses, the shortest way imo would be to use your knowledge of binomial distributions, but in this case n=3 that probably doesn't even count as a simplification.

Just how much work are you talking about when you say "manually"?

You've already found out the probability of 3 correct P(3 correct), and P(≥2 correct) is just P(2 correct) + P(3 correct).

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