Hi can anyone help me on this?
I am trying to understand how can I give a mathematical expression for the following Minitab output.
Sales=7.2 + 0.42Timesq + 27 Q1 + 56.2Q2 + 18.8Q3
I am confused with the fact that I have Time square. I know that if we have a quadratic trend we should use:
However, the Minitab output only shows timeSq. Should I use: