The Sensitivity Analysis Tool is simple to use. Firstly, you need to specify a ranges of values to iterate over. The range is specified by a high value, a low value and a count of the number of points (including the high and low values). You will also need to specify the cell into which these values will be input. This should be an input cell for the formula you are analyzing. For instance, if you were analyzing an option portfolio, you might specify the Volatility input as the X value cell.
Repeat this process for the Y values. This is the second dimension of the analysis  for instance, continuing the example above you might choose to iterate over the RiskFree Rate for the Y values.
Next, you need to specify the value that will be measured at each iteration. This should be the output of the function being analyzed. For example, the cell containing the calculated option value.
Finally, hit the 'Create Graph' button and the Sensitivity Analysis Tool will run the analysis, generate the set of output values and create a graph.
