SOLUTION: 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

Algebra ->  Probability-and-statistics -> SOLUTION: 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      Log On


   

Question 128644: 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) About Me  (Show Source):
You can put this solution on YOUR website!
I assume you use the t-distribution for confidence intervals
for population means and z-distribution for confidence
intervals for population proportions.
Error is the standard error:
E = t*(s/sqrt(n))
Your t* depends on alpha and is always two-tailed for CI's.
Your s is the standard deviation of your sample
Your n is your sample size.
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Cheers,
Stan H.