There are many resources you can access that will include statistical data. For example, the national census, conducted every 10 years, is rich with data. However, that data becomes stale after a few years. States, counties, and municipalities often collect data for public use. This can include city planning documents, health department reports, and school system reports. Some non-profits also fund data collection. Universities, philanthropic organizations, and foundations are often a good source of data.
Primary data collected from surveys, interviews and focus groups can help provide a more narrow perspective, down to the area of specific neighborhoods, populations, ages, and ethnic groups. Use these research methods for both quantitative and qualitative data.