(40%) 2. Several ovens in a metal working shop are used to heat metal specimens. All ovens are supposed to operate at the same temperature, although it is suspected that this may not be true. Three ovens are selected at random and their temperatures on successive heats are noted. The data collected are as follows. Temperature sample mean sample variance 498.3 498.1 494.1 495.5 10.85 484.6 479.7 477.3 482.5 24.7 486.9 491.6 487.3 487.2 12.37 (20%) (a) Is there a signicant variation in temperature between ovens in the shop? Use a = 0.05. (10%) (b) Write a statistical model for this experiment and state assumptions associated with the elements in the model. Estimate all parameters in the model. (10%) (c) Find a 95% confidence interval for the mean temperature for all ovens in the shop