According to a dietary study, high sodium in- take may be related to ulcers, stomach cancer, and migraine headaches. the human requirement for salt is only 220 milligrams per day, which is surpassed in most single servings of ready-to-eat cereals. if a random sample of 20 similar servings of a certain cereal has a mean sodium content of 244 milligrams and a standard deviation of 24.5 milligrams, does this sug- gest at the 0.05 level of significance that the average sodium content for a single serving of such cereal is greater than 220 milligrams? assume the distribution of sodium contents to be normal.