A government agency received many consumers' complaints that boxes of cereal sold by a company contain less than the advertised weight of 20 oz of cereal with a standard deviation of 5 oz. To check the consumers' complaints, the agency bought 36 boxes of the cereal and found that the average weight of cereal was 18 oz. If the amount of cereal in the boxes is normally distributed, test the consumers' complaint at the 0.05 level of significance.