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# S2 help asap

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1. http://www.ocr.org.uk/Images/242460-...atistics-2.pdf

Q7i and ii

Why for one of them have they divided by square root of 50 and the other they haven't?

Why doesn't it apply for both?
2. (Original post by Super199)
http://www.ocr.org.uk/Images/242460-...atistics-2.pdf

Q7i and ii

Why for one of them have they divided by square root of 50 and the other they haven't?

Why doesn't it apply for both?
Because in one case you are dealing with the distribution of the times taken by the candidates and in the other you are dealing with the distribution of the mean of times taken by the candidates. If the times are normally distributed with mean and standard devation , then the distribution of mean scores is normal with mean and standard deviation .

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