Are children heavier now than they were in the past? The National Health and Nutrition Examination Survey (NHANES) published in 2004 reported that the mean weight of six-year-old girls in the United States was 49.3 pounds. Another NHANES survey, published in 2012, reported that a sample of 177 six-year-old girls had an average weight of 51.9 pounds. Assume the population standard deviation is σ = 17 pounds. Can you conclude that the mean weight of six-year-old girls is higher in 2012 than in 2004? Use the α = 0.01 level of significance.