Sol does more research and reads a few different articles. He writes a conclusion about the data he has used and the articles he has read. In his summary, he uses data from the articles.
What must his summary include?

When conducting research and using secondary data or information from other sources (like articles), it is essential to acknowledge where that information came from. This is called citing sources or providing references. It is a fundamental part of the statistical enquiry cycle and academic integrity. It allows others to verify the information, shows that the research is based on credible evidence, and gives credit to the original authors. Therefore, Sol's summary must include references to the articles he read.