Question: A more accurate line equation

Hello, thanks for reading this:

I have a bunch of points (x,y). I turned the points into a graph and then asked maple to give me the equation to the line.

It's mostly accurate however,..it's not close enough.

When I test the equation I can see some deviation from where it should be.

In some places the deviation is rather significant.

Does anyone know what I can do to get this more accurate??

Thank you!!!

  
Here is what I have done (I am using maple 13):

restart;
  with(Statistics);
  with(plots);
  X := Vector([10, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 250, 300,
  350, 400, 450, 500, 550, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400,
  1500, 1600, 1700, 1800, 1900, 2000, 3000]);
  Y := Vector([1, 7, 39, 65, 103, 127, 151, 177, 204, 221, 251, 300, 327, 391,
  428, 469, 496, 525, 559, 595, 631, 659, 683, 711, 728, 748, 772, 779, 795,
  807, 827, 832, 845, 976]);
             /                 2        3           \
  fit1 := Fit\a + b ADC + c ADC  + d ADC , X, Y, ADC/;
  points := {seq([X[i], Y[i]], i = 1 .. 34)};
  pointplot(points);
  plot(fit1, ADC = 0 .. 1000);