Question #4dab6
1 Answer
Jul 3, 2017
The y-axis is the value index in this case.
Explanation:
An index is a convenient way to show relative changes over time. The '100' is the full value at some point in time, as in 100%. Then as the value changes (up or down) over time it is easy to see the relative amount of the change.
For example, a point at '80' would mean that the value fell to 80% of the "index" value. And a point at '200' would mean that the value is now at 200%, or twice the original or index value.
This makes it easy to compare the relative change of different-priced items, such as stocks in this chart. It doesn't matter if one stock was 50 and another was 75 at the start. The index shows which increased (or decreased) the most over the time period shown.
