Class 9 · Mathematics · New NCERT
Chapter 10: How Quantities Combine: Understanding Data
Chapter 10 extends the idea of the average to the weighted average. It shows why an average of averages must account for group sizes, applies weighted means to mixtures, custom weights, ratings and marks, and then introduces stacked bar charts and 100% stacked bar charts as ways to visualise and interpret data, including what each chart can and cannot tell us.
Topics covered
- Average of averages
- Mixtures and concentration
- Weighted mean with custom weights
- Stacked bar charts
- 100% stacked bar charts and their interpretation