Let us say Sixto and a group of his classmates would want to study the consumption patterns of a municipality which has a population of 10,000 families. They would like to draw 1,000 sample units from this population. The clerk from the municipal hall provided them with the following information: 500 families belong to the high-income group; 2,500 families to the middle-income group; and 7,000 families to the low-income group. Based on this information, how can Sixto and his friends pick 1,000 sample units proportionate to the aforementioned income classification? Demonstrate your sample distribution by constructing a table. Use MS Excel/Google Sheets formula for your calculations.