I have a table of XY values. For a value of X entered that is the exact number from the table, I used the vlookup() function to get the Y value. However, If I would enter a value of X that is not located in the table but is between an upper and lower values shown in the table, than I would like to average the corresponding Y values. Attached is a spreadsheet that I am working on. I am trying to figure out the equation that I should use in this case.