A random sample of 15 tootsie rolls were taken from a bag. Each piece weighed in at 3.087; 3.131; 3.241 3.241; 3.270; 3.353; 3.400; 3.400; 3.408; 3.411; 3.435; 3.437; 3.437; 3.439; 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 +- 0.02 grams with 90 percent confidence? (c) Discuss the factors which might cause variation in the weight of tootsie rolls during manufacture.

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