Question

Suppose that a steel manufacturing company wishes to know whether the tensile strength of

the steel wire has an overall average of 120 pounds. A sample of 25 units of steel wire produced

by the company yields a mean strength of 110pounds and a variance of 144 pounds. Should the

company conclude that the strength is not 120 pounds with α=0.05? Obtain a 95% confidence

interval for the true mean.​

Answer 1

Answer:

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