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# normal distribution watch

1. can someone explain this to me please
X = the height of chairs (cm)
X has a mean of 60 and a standard deviation of 2. A random sample of 400 chairs made is taken.
Find then mean and SD of X(bar)
2. not sure if you have enough info?
not sure if you have enough info?
see thats what i thought i dunno though
4. Are you sure that's all the info given. If yh then surely the mean is 60 and the SD is 2 :s
5. i think you have not enough info. if it gave you a probability you could then look back on your percentage tables to find a z value and then use simultaneous eqs to find x-bar and s.d.
6. (Original post by nushii)
can someone explain this to me please
X = the height of chairs (cm)
X has a mean of 60 and a standard deviation of 2. A random sample of 400 chairs made is taken.
Find then mean and SD of X(bar)
H~N(60, 2^2)

write it out like this.. and you should have more information than the random sample.
i think you have not enough info. if it gave you a probability you could then look back on your percentage tables to find a z value and then use simultaneous eqs to find x-bar and s.d.
okay then i'll try that thank yu

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