A chef in a restaurant that specializes in pasta dishes was experiencing difficulty in getting brands of pasta to be al dente-that is, cooked enough so as not to feel starchy or hard but still feel firm when bit-ten into. She decided to conduct an experiment in which two brands of pasta, one American and one Italian, were cooked for either 4 or 8 minutes. The variable of interest was weight of the pasta because cooking the pasta enables it to absorb water. A pasta with a faster rate of water absorption may provide a shorter interval in which the pasta is al dente, thereby increasing the chance that it might be overcooked. The experiment was conducted by using 150 grams of uncooked pasta. Each trial began by bringing a pot containing 6 quarts of cold, unsalted water to a moderate boil. The 150 grams of uncooked pasta was added and then weighed after a given period of time by lifting the pasta from the pot via a built-in strainer. The results (in terms of weight in grams) for two replicates of each type of pasta and cooking time are stored in Pasta and are as follows:

At the 0.05 level of significance,
a. Is there an interaction between type of pasta and cooking time?
b. Is there an effect due to type of pasta?
c. Is there an effect due to cooking time?
d. Plot the mean weight for each type of pasta for each cooking time.
e. What conclusions can you reach concerning the impor¬tance of each of these two factors on the weight of the pasta?