Medical wires are used in the manufacture of cardiovascular devices. A study was conducted to determine the effect of several factors on the ratio of the load on a test specimen (YS) to the ultimate tensile strength (UTS). The file MedicalWires1 contains the study results, which examined factors including the machine (W95 vs. W96) and the reduction angle (narrow vs. wide). (Data extracted from B. Nepal, S. Mohanty, and L. Kay, "Quality Improvement of Medical Wire Manufacturing Process," Quality Engineering 25, 2013, pp. 151-163.)

At the 0.05 level of significance,

a. is there an interaction between machine type and reduction angle?

b. is there an effect due to machine type?

c. is there an effect due to reduction angle?

d. Plot the mean ratio of the load on a test specimen (YS) to the ultimate tensile strength (UTS) for each machine type for each reduction angle.

e. What can you conclude about the effects of machine type and reduction angle on the ratio of the load on a test specimen (YS) to the ultimate tensile strength (UTS)? Explain.