A machine produces metal rods used in an automobile suspension system. A random sample of 12...

80.2K

Verified Solution

Question

Statistics

A machine produces metal rods used in an automobile suspensionsystem. A random sample of 12 rods is selected and the diameter ismeasured. The resulting data, in mm, are shown here:
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
3.11 Â Â Â 2.88Â Â Â Â 3.08Â Â Â Â 3.01
2.84Â Â Â Â 2.86Â Â Â Â 3.04Â Â Â Â 3.09
3.08Â Â Â Â 2.89Â Â Â Â 3.12Â Â Â Â 2.98
a.Â Â Â Â Â Â Â Â Find a two-sided95% confidence interval for the mean rod diameter. State theassumption necessary to find the confidenceinterval.Â Â
Is there any evidence to indicate that mean rod diameter isdifferent from 2.95 at significance level a = 0.05? Write theappropriate hypothesis. Make required assumption(s).
Can you make the same decision as in part b. from the result ofpart a. without testing the Hypothesis? If yes, how?

Answer & Explanation Solved by verified expert

3.8 Ratings (561 Votes)

n 12Sample meanRound to 3 decimalSample standard deviations 01050 Round to 4 decimalaAssumptions for confidence intervali Data must be from a random sample from large populationii Observations in the sample must be independent of eachotherHere population standard deviation is not known so we use tintervalConfidence level See Answer

Get Answers to Unlimited Questions

Join us to gain access to millions of questions and expert answers. Enjoy exclusive benefits tailored just for you!

Membership Benefits:

Unlimited Question Access with detailed Answers
Zin AI - 3 Million Words
10 Dall-E 3 Images
20 Plot Generations
Conversation with Dialogue Memory
No Ads, Ever!
Access to Our Best AI Platform: Flex AI - Your personal assistant for all your inquiries!

Become a Member