Which is an example of qualitative secondary sources as per the provided evaluations?

Qualitative secondary sources provide insights through non-numeric data that reflect personal experiences, opinions, and narratives. Personal letters or diaries exemplify this type of source as they document individual thoughts and feelings, offering a rich narrative that can reveal social contexts, relationships, and cultural norms. These sources are often analyzed for their thematic content, allowing researchers to explore the complexities of human experience in societal settings.

In contrast, the other options listed represent quantitative data that lend themselves to statistical analysis rather than in-depth qualitative insight. Statistical reports, census data, and crime statistics are all forms of quantitative data that provide numerical information, trends, and patterns, which do not delve into the nuanced personal experiences that qualitative data captures. Therefore, personal letters and diaries stand out as the correct example of qualitative secondary sources in this context.