The estimated distribution (in millions) of the population by age in a certain country for the year 2015 is Under 4 years: 21.6 shown in the pie chart. Make a frequency distribution for the data. Then use the table to estimate the 5-14 years: 45.7 sample mean and the sample standard deviation of the data set. Use 70 as the midpoint for "65 years and 15-19 years: 18.4 over." 20-24 years: 22.4 25-34 years: 46.8 35-44 years: 37.1 45-64 years: 78.3 65 years and over: 52.7 . . . The sample mean is x= (Round to two decimal places as needed.)