A casting company has several ovens in which they heat the raw materials prior to pouring them into a wax mold. It is very important that these metals be heated to a precise temperature with very little variation. Three ovens are selected at random, and their temperatures are recorded (°C) very accurately on 10 successive heats. The collected data are as follows:

a. Is there significant evidence (α = .05) that the three ovens have different levels of variation in their temperatures?
b. Assess the order of magnitude in the differences in standard deviations by placing 95% confidence intervals on the ratios of the three pairs of standard deviations.
c. Do the conditions that are required by your statistical procedures in parts (a) and (b) appear to be valid?

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Oven Temperature C 1 1,670.87 1,67088 1671.51 1,672.01 1,669.63 1,670.95 1,66870 1,671.86 1,669.12 1.672.52 2 1.66916 1.66960 1669.76 1,66918 1,671.92 1669.69 1.66945 1,669.35 1,671.89 1,67345 3 1,673.08 1,672.75 1675.14 1,67494 1,671.33 1,660.38 1,679.94 1,66051 1,66878 1,664.32