SPSS will draw a quadratic fit line on a scatterplot if requested and provide the formula (see attached).

I have typed out the quadratic formula below; see any errors?

y = (-5870) + 6.11x + (-.00157)x^2

The problem is that when I work out y by hand or use a graphing calculator (e.g., Desmos), I get values that don't jibe with the data. For instance, the graph shows x=1960, y~95 whereas by hand and a graphing calculator show x=1960,y~74.

What could I be doing wrong?

Thanks!

Hans

PS-I'm off to bed, so I'll check this tomorrow. Thanks!