I have minimum, average and maximum values of something in columns. I have, for example, 24 values (I have a lot more). I am making a graph in Excel (funcional dependance) from minimum values and average values and from maximum values and average values. The graphs are plotted as Scatters and on the Scatters I am adding chart element Trendline (Polynomial with Order 6). From that Trendline I can get the functions (average function is the same). I have 2 functions for a case: 1. Case Minimum and Averages average function: y=0.0012x^6-0.0291x^5-0.1902x^4+10.253x^3-94.323x^2+315.61x-144.16 R^2=0.5326 minimum function: y=0.0024x^6-0.0846x^5+0.895x^4-0.425x^3-42.315x^2+210.33x-153.26 R^2=0.4506 2. Case Maximum and Averages average function: y=0.0012x^6-0.0291x^5-0.1902x^4+10.253x^3-94.323x^2+315.61x-144.16 R^2=0.5326 maximum function: y=0.0092x^6-0.4147x^5+7.0073x^4-55.137x^3+204.17x^2-312.59x+401.71 R^2=0.6944 My problem here is that for the same function I want to write one value for minimum and one for maximum and to get the graph for that values in the same graph form as now. It is somehow a prediction, I want to see for the same function if I got different minimum and maximum values what will I get. How can I do this in Excel? Thank you in advance. I will appreciate your answers.