The starch suspension contained 0.8g of starch

calculate the mean rate of starch digested at 33 degrees

In order to determine the rate of digestion, we also require the initial amount of starch that was present and the time taken for it to reach the final amount of 0.8 grams. Once we have this information, we may apply:

Rate of digestion = (initial amount - 0.8) / time taken

This will tell us the rate of digestion in grams per unit time.