# S2 Sampling Help Please

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Thread starter 15 years ago
#1
The masses of kilogram bags of flour produced in a factory have a normal distribution with mean 1.005 and SD 0.0082. A shelf in the store is loaded with 22 of these bags, assumed to be a random sample.

[a] find the probability that a randomnly chosen bag has mass less than than 1.000

[b] find the provbability that the mean mass of the 22 bags is less than 1.000
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Thread starter 15 years ago
#2
btw part [a] is ok, i understand that is straight nd, with part [b] do I need to use the central limit theorem?
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15 years ago
#3
(Original post by Sang)
The masses of kilogram bags of flour produced in a factory have a normal distribution with mean 1.005 and SD 0.0082. A shelf in the store is loaded with 22 of these bags, assumed to be a random sample.

[a] find the probability that a randomnly chosen bag has mass less than than 1.000

[b] find the provbability that the mean mass of the 22 bags is less than 1.000
0
15 years ago
#4
(Original post by Sang)
The masses of kilogram bags of flour produced in a factory have a normal distribution with mean 1.005 and SD 0.0082. A shelf in the store is loaded with 22 of these bags, assumed to be a random sample.

[a] find the probability that a randomnly chosen bag has mass less than than 1.000

[b] find the provbability that the mean mass of the 22 bags is less than 1.000
∫ ² ³ ± ÷ ° √ ∂ ∞ ≈ ≠ ≡ ≥ ≤ ø Ø ½ ¼ « » µ π

b) X-N(1.005,0.0082²) becomes X(bar)-N(1.005,0.0082²/22). Yes you do use the CLT, it doesn't matter what size 'n' is, as we are told the original distribution follows a normal, therefore if n had been 4 we would still use the CLT for the sample.
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15 years ago
#5
wtf is the central limit theorum??
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