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Solved: To obtain information on the corrosion-resistance
Chapter 8, Problem 22E(choose chapter or problem)
Problem 22E
To obtain information on the corrosion-resistance properties of a certain type of steel conduit, 45 specimens are buried in soil for a 2-year period. The maximum penetration (in mils) for each specimen is then measured, yielding a sample average penetration of and a sample standard deviation of s = 408. The conduits were manufactured with the specification that true average penetration be at most 50 mils. They will be used unless it can be demonstrated conclusively that the specification has not been met. What would you conclude?
Questions & Answers
QUESTION:
Problem 22E
To obtain information on the corrosion-resistance properties of a certain type of steel conduit, 45 specimens are buried in soil for a 2-year period. The maximum penetration (in mils) for each specimen is then measured, yielding a sample average penetration of and a sample standard deviation of s = 408. The conduits were manufactured with the specification that true average penetration be at most 50 mils. They will be used unless it can be demonstrated conclusively that the specification has not been met. What would you conclude?
ANSWER:
Step 1 of 2
Given that,
To obtain information on the corrosion-resistance properties of a certain type of steel conduit, n = 45 specimens are buried in soil for a 2-year period.
The maximum penetration (in mils) for each specimen is then measured, yielding a sample average penetration of 
The conduits were manufactured with the specification that true average penetration be at most 50 mils.
Let the true average penetration be 