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 3.087 3.131 3.241 3.241 3.270

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Question 233646: 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 3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477
(a) Construct a 90 percent confidence interval for the true mean weight. (b) What sample size
would be necessary to estimate the true weight with an error of � 0.03 grams with 90 percent confidence?
(c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during
manufacture. (Data are from a project by MBA student Henry Scussel.)

Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
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 3.087 3.131 3.241 3.241 3.270 3.353 3.400 3.411 3.437 3.477
(a) Construct a 90 percent confidence interval for the true mean weight.
sample mean = 3.3048 ; sample std = 0.13199
standard error: 1.645*0.13199/Sqrt(10) = 0.06866
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90% CI: 3.3048-0.06866 < u < 3.3048+0.06866
90% CI:3.23614 < u < 3.37346
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(b) What sample size would be necessary to estimate the true weight with an error of � 0.03 grams with 90 percent confidence?
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n = [1.645*0.13199/0.03]^2 = 7.24^2 = 52.38
Round up to get n = 53
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(c) Discuss the factors which might cause variation in the weight of Tootsie Rolls during manufacture. (Data are from a project by MBA student Henry Scussel.)
I'll leave that to you.
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Cheers,
Stan H.