The article “Application of Surgical Navigation toTotal Hip Arthroplasty” reports that in a sample of 123 hip surgeries of a certain type, the average surgery time was 136.9 minutes with a standard deviation of 22.6 minutes.
a. Find a 95% confidence interval for the mean surgery time for this procedure.
b. Find a 99.5% confidence interval for the mean surgery time for this procedure.
c. A surgeon claims that the mean surgery time is between 133.9 and 139.9 minutes. With what level of confidence can this statement be made?
d. Approximately how many surgeries must be sampled so that a 95% confidence interval will specify the mean to within ±3 minutes?
e. Approximately how many surgeries must be sampled so that a 99% confidence interval will specify the mean to within ±3 minutes?
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A(n) ____________________ allows for smooth and partial engagement and disengagement of the torque converter clutch.
Fill in the blank(s) with the appropriate word(s).
Jensen Systems purchases several parts for the instruments it makes via a fixed-price contract of $155,000 per year from a local supplier. The new president of Jensen wants to make the parts in-house through the purchase of equipment that will have a first cost of $240,000 with an estimated salvage value of $30,000 after 5 years. The AOC is difficult to estimate, but company engineers have made optimistic, most likely, and pessimistic estimates of $70,000, $85,000, and $120,000 per year, respectively. Determine if the company should purchase the equipment under any of the operating cost scenarios. The MARR is 20% per year.
What will be an ideal response?
A ball bearing that is on a shaft or in a housing should be removed:
A) By applying pressure only to the race that is supported securely B) Only by pressing on the inner race when the outer race is in a housing or by pushing on the outer race when the inner race is on a shaft C) By pressing on and supporting any part of the bearing that is available D) B and C above
When only a part of a surface is to be designated as a datum, a ____ line drawn parallel to the surface is used to indicate the portion of the surface acting as the datum.
A. center B. chain C. visible D. cutting-plane