SOLUTION: (8.46) A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were 3.18 3.21 3.15 3.42 3.2

Question 478722: (8.46) A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale. The results in grams were
3.18
3.21
3.15
3.42
3.23
3.36
3.47
3.29
3.37
3.40

(a) Construct a 95 percent confidence interval for the true mean weight.
(b) What sample size would be necessary to estimate the true weight with an error of � 0.01 grams with 99 percent confidence? (Hint: Use sample size calculation for means.)
(c) What factors might cause variation in the weight of Tootsie Rolls during manufacture?

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
3.18
3.21
3.15
3.42
3.23
3.36
3.47
3.29
3.37
3.40

I used a TI-84 on the data to get the following:
(a) Construct a 95 percent confidence interval for the true mean weight.
T-interval: 3.2285 < p < 3.3875
---------------------------
(b) What sample size would be necessary to estimate the true weight with an error of � 0.01 grams with 99 percent confidence? (Hint: Use sample size calculation for means.)
---
n = [z*s/E]^2 = [2.58*0.105/0.01]^2 = 734 when rounded up
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Cheers,
Stan H.

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