how to find the average velocity and speed for an entire postion time graph

Answer 1

(1) Pick the times you want to average over. Call them t2 and t1.

(2) Measure the distance change, x2 - x1.
The average velocity is ((x2 - x1)/(t2 - t1)

(3) The average speed is harder.
You need to plot the instantaneous speed |x'(t)| and average that

I am assuming motion in one dimension on ly. If two or three dimensional, you must use vectors.