Index Numbers Index Numbers You will remember that in order to change a series of nominal dollars into real dollars, you use a price index . Index numbers in general are numbers that are expressed as a percentage of some given base number. In terms of an index number, output would be 100 and 117 for the two years.
Index numbers are VERY EASY to construct from a series of data.
Let's construct an index number series for annual Wabash tuition. 168.07 176.82 187.44 Notice that the index number for the base year is always 100. This can be nicely graphed using the chart facility in Excel, as shown below. Note that index numbers have no units. Occasionally two indices are combined to produce one composite index.