Slope is 1 or -1

Are you better at estimating where the slope is 1 or where the slope is -1?

Drag point P to the point on the curve where you think the slope is 1. Drag point Q to the point on the curve where you think the slope is –1. Click on SUBMIT when you have placed the points! How close do you get? Enter your data in the google form at the bottom of this page.

The data