Small sample mean problem. the maker of potato chips uses an automated packaging machine to pack its 20-ounce bag of chips. at the end of every shift 18 bags are selected at random and tested to see if the equipment needs to be readjusted. after one shift, a sample of 18 bags yielded the following data. mean = 20.45 s = .80 n = 18. if we were to conduct a test to see if the sample estimate is different from the company’s expected weight of 20 oz. at an alpha level = .05, what is (are) the critical t-value(s) for this test? group of answer choices