For a random sample of 50 measurements of the breaking strength of cotton threads resulting in...

For a random sample of 50 measurements of the breaking strength of cotton threads resulting in a mean of 210 grams and standard deviation of 18 grams.

A. Calculate an 80% confidence interval for the true mean breaking strength of cotton threads.

B. Is your interval statistically valid? Explain.

C. Without recalculating, would a 90% confidence result in a wider or narrower interval? Explain.

D. A co-worker offers the following partial interpretation of your interval: We are confident that 80% of all breaking strength measurements of cotton threads will be within this calculated confidence interval. Explain why this interpretation is not correct.

E. Provide an interpretation of your confidence interval.

F.Use R to find the confidence interval you found by hand in the question. Include a copy of your interval and the R commands.

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Expert Solution

orchestra answered 1 year ago

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