A cake can be produced by using a 400-degree, 300-degree, or 200-degree oven. In the file cakes.xlsx you are given the quality level of cakes produced when the cakes are baked at different temperatures. Does temperature appear to influence cake quality? What is the range of cake quality that you are 95 percent sure will be produced with a 200-degree oven? If you believe that the size of the oven used influences cake quality, does this analysis remain valid?