Now create a custom formula to combine or transform the series.
For example, invert an exchange rate by using formula 1/a, where “a” refers to the first FRED data series added to this line. Or calculate the spread between 2 interest rates, a and b, by using the formula a - b.
Use the assigned data series variables (a, b, c, etc.) together with operators (+, -, *, /, ^, etc.), parentheses and constants (1, 1.5, 2, etc.) to create your own formula (e.g., 1/a, a-b, (a+b)/2, (a/(a+b+c))*100). As noted above, you may add other data series to this line before entering a formula.
