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A machine manufactures bolts to a set length. A random sample of 20 bolts is checked...

A machine manufactures bolts to a set length. A random sample of 20 bolts is checked and found to have a mean length of 75.2 mm and standard deviation of 2.5 mm.

a. Find the 99% confidence interval for the mean length of the bolts. _____

b. The maximum error E = _____

math   Statistics-And-Probability   
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