The lesson focuses on histograms, illustrating how to create histograms with different group intervals, such as 5 or 10. It uses a fishing competition example to demonstrate the distribution of fish weights, highlighting that 21 participants caught between 0 and 10 kilograms, and 7 participants caught between 10 and 20 kilograms. The instructor emphasizes organizing data into intervals and correctly placing the values within these ranges for accurate representation.