<PRE><B>Question 203938</B>
A random sample of 10 miniature Tootsie Rolls was taken from a bag. Each piece was weighed on a very accurate scale.
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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
Sample mean: 3.3048
Standard Dev: 0.13199
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(a) Construct a 90 percent confidence interval for the true mean weight.
Using a TI calculator and a T-Interval I get: (3.2283 , 3.3813)
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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% confidence?
n = [1.645*0.13199/0.03]^2 = 7.237..^2 = 52.2
Rounding up you 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&#39;ll leave that discussion to you.
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Cheers,
Stan H.
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