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# Statistics HELP PLEASEEEEEE! watch

1. In a random sample of 1000 body feathers from birds of this species, how many would the researcher expect to find with lengths more than 1 standard deviation from the mean? [4]

Please explain in a way that is understandable , I really tried to understand I just don’t get the answer (317)
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2. Is this normal distribution? If so it would be 1000 x P(X>1+s.d.)
3. (Original post by Radioactivedecay)
Is this normal distribution? If so it would be 1000 x P(X>1+s.d.)
And how much would the s.d be ?
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4. (Original post by Radioactivedecay)
Is this normal distribution? If so it would be 1000 x P(X>1+s.d.)
It is 1 right ? The sd is 1
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5. (Original post by Sammysammy99)
In a random sample of 1000 body feathers from birds of this species, how many would the researcher expect to find with lengths more than 1 standard deviation from the mean? [4]

Please explain in a way that is understandable , I really tried to understand I just don’t get the answer (317)
Refer to the normal distribution diagram I posted on your other thread.

If we are looking for feathers of lengths MORE than 1 standards deviation away, we are interested in the right-most and left-most portions of the distribution that are beyond and . By looking at the percentages, this is simply the case of obtaining the probability of having the feathers greater than of length 1+(1 s.d.) or less than 1-(1 s.d.) which is just 2(13.6% + 2.1% + 0.1%) = 31.6% or so.

The rest is just applying it on the sample for the approximation.

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