A soft-drink manufacturer claims that its 12-ounce cans do not contain, on average, more than 30 calories. A random sample of 16 cans of this soft drink, which were checked for calories, contained a mean of 31.8 calories with a standard deviation of 3 calories. Assume that the number of calories in 12-ounce soda cans is normally distributed. State the null and alternative hypotheses to test the manufacturer claim.