Index Numbers

 10.1 Index Numbers
 $$\blacksquare$$ An index number is a measure that shows the change in a quantity at a specific time compared to the base time. $$\blacksquare$$ The value of the quantity at the base time is conventionally given the number $$100$$, and the index number of any other time is in proportion with it. $$\blacksquare$$ The formula for index number is

\boxed{ \begin{aligned} I&=\dfrac{Q_1}{Q_0} \times 100 \end{aligned}}

 where $$Q_0=$$quantity at the base time $$Q_1=$$quantity at a specific time Example: A school canteen made a profit of $$\text{RM }50 \,000$$ in the year $$2\,017$$ and $$\text{RM }78 \,000$$ in the year $$2\,019$$. Calculate the index number to show the change in profit for the school canteen in the year $$2\,019$$ based on the year $$2\,017$$. Based on the question, $$Q_0=$$profit in the year $$2\,017$$ $$Q_1=$$profit in the year $$2\,019$$ Index number,

\begin{aligned} I&=\dfrac{Q_1}{Q_0} \times 100 \\\\&=\dfrac{78 \,000}{50 \,000} \times 100 \\\\ &=156. \end{aligned}