HP 48G Linear Regression Best Fit Line

[MNH]

(12-23-2021 01:07 PM)Rodger Rosenbaum Wrote:  When you execute ORTH the first number (.008321172 for the data we've been testing with) is the slope. The angle the line makes with the x axis is just the atan of the slope.

Perfect! I get 0.476757033 decimal degrees, which equals 0°28'36". That would be in the first (northeast) quadrant turning clockwise from 0° north. I have to test the slope angle in all 4 quadrants because the angle might be restricted to 0° through 90°. I'm wondering if the slope angle for quadrants 3 (southwest) and 4 (northwest) would be a negative number because the x-values in those quadrants are negative.

Another thing I have to do is get coordinates for both ends of the BFL. Depending on which direction I'm coming from along the line, I need to be able to define the line by entering a coordinate and a direction. In this case our line runs on an azimuth of 0°28'36" (N 0°28'36" E) along the west side of a road. I will need to check the perpendicular offsets from our line to points on the other side of the road. Coordinates will be necessary to do this.