The curve y = 2x+3 is U shaped, the curve y = -2x+3 has an inverted U shape
It's all in the math. Google on the word "parabola" to learn more
best wishes
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"jimshoe40" wrote in message
...
I added a polynomial trend line with an order of 2 and it is higher in the
middle than on the ends. I did this with a different data series and it
was
lower in the middle than on the ends. Can anyone tell me why it curves up
or
down?