Question: The Centers for Disease Control and other organizations are interested in the health benefits of breast-feeding for infants. The National Immunization Survey includes questions about breast-feeding practices, including the question: "How long was [your child] breast-fed or fed breast milk?" The data for duration of breast-feeding, in months, for 20 hypothetical mothers are presented below.
a. Create a frequency table for these data. Include a third column for percentages.
b. Create a grouped frequency table for these data with three groups (create groupings around the midpoints of 2.5 months, 7.5 months, and 12.5\ months).