2.3 Economic Data LO 4
Index numbers express economic series in relative form. Values in
each period are expressed in relation to the value in the base period,
which is given a value of 100.
Economic data can be graphed in three different ways. Cross-
sectional graphs show observations taken at the same time. Time-
series graphs show observations on one variable taken over time.
Scatter diagrams show many points, each of which refers to specific
observations on two different variables.