Meticulous Drill & Reamer (MD&R) specializes in drilling and boring precise holes in hard metals (e.g., steel alloys, tungsten carbide, and titanium). The company recently contracted to drill holes with 3-centimeter diameters in large carbon-steel alloy disks, and it will have to purchase a special drill to complete this job. MD&R has eliminated all but two of the drills it has been considering: Davis Drills’ T2005 and Worth Industrial Tools’ AZ100. These producers have each agreed to allow MD&R to use a T2005 and an AZ100 for one week to determine which drill it will purchase. During the one-week trial, MD&R uses each of these drills to drill 31 holes with a target diameter of 3 centimeters in one large carbon-steel alloy disk, then measures the diameter of each hole and records the results. MD&R’s results are provided in the table that follows and are available in the file MeticulousDrills.  

MD&R wants to consider both the accuracy (closeness of the diameter to 3 centimeters) and the precision (the variance of the diameter) of the holes drilled by the T2005 and the AZ100 when deciding which model to purchase.

Managerial Report

In making this assessment for MD&R, consider the following four questions:

1. Are the holes drilled by the T2005 or the AZ100 more accurate? That is, which model of drill produces holes with a mean diameter closer to 3 centimeters?
2. Are the holes drilled by the T2005 or the AZ100 more precise? That is, which model of drill produces holes with a smaller variance?
3. Conduct a test of the hypothesis that the T2005 and the AZ100 are equally precise (that is, have equal variances) at a=0.05. Discuss your findings.
4. Which drill do you recommend to MD&R? Why?

Initial post prompt: Your Managerial Report serves as your initial post to the discussion forum. After responding to the requirements posed by the Managerial Report, also provide an example in your career in which you believe one of the lessons learned from the Case has been/could be applicable. Alternatively, if you don't have/foresee direct experience relevant to your current position, what type of scenario can you anticipate occurring where you can utilize one of the lessons learned from examining this case?

Response post prompt: Consider Managerial Reports posted by two of your peers. One or both of your responses may be to Managerial Reports for a case problem different from your own. Think critically and ask open-ended questions. If you agree, consider their position and expand upon their ideas. Provide an additional perspective. If you disagree, provide your reasoning. Always be professional and courteous in your responses.