(These data are taken ·from U.S. Patent 3,505,079 for a process preparing a dry free-flowing baking mix.) Five recipes were used for making a number of cakes, starting from two different types of premix, A and B. The difference between the two premixes was that A was aerated and 8 was not. The volumes of the cakes were measured with the following results:
The recipes differed somewhat in the amount of water added, beating time, baking temperature, and baking time. The patent claims that significantly greater volume was obtained· with A. Do these data support this claim? Make any relevant comments you think are appropriate. Include in your answer a calculated 95% confidence interval for the true difference between the volumes obtained with A and B. State any assumptions you make.