The following data represent the number of people aged 25 to 64 years covered by health insurance (private or government) in 2018. Approximate the mean and standard deviation for age. Age 25-34 35-44 45-54 55-64 Number (millions) 21.6 33.5 31.4 22.7 (Type an integer or decimal rounded to two decimal places as needed.) (Type an integer or decimal rounded to two decimal places as needed.)