CBSE Notes for Statistics for Economics Chapter 8
An index number is not an absolute measure, it measures the percentage change in a variable over time. It does so by comparing the value of a variable at present to its value at a base year. Index number gives a quantitative foundation to qualitative statements like prices are falling or rising. Lastly, index numbers show changes in average. In effect, it means if the average change is 5% then some goods might not change exactly at 5%. Please refer Statistics for Economics Class 11 Notes Chapter 8 for more information.
CBSE Revision Notes 