Here are the main points that are addressed in the video. Please read these and think about them as you watch.

Average Rate of Change – Video 1

• Speed is a quantification of motion.
• An object’s speed is not an arithmetic mean of “instantaneous” speeds.
• The average speed of an object in motion is always with reference to some interval of time.
• The average speed of an object over the interval of time from $t_1$ to $t_2$ is the constant speed at which another object would have to travel to cover the same distance as the first object in the same amount of time. This constant speed is computed as a ratio of changes in distance and corresponding changes in time.

Average Rate of Change – Video 2

• Average rate of change is a way of characterizing the variation of input and output quantities of a non-linear function. It is a tool for describing the relationship between covarying quantities.
• A function’s average rate of change is not an arithmetic mean of “instantaneous” rates of change.
• A function’s average rate of change is always with reference to some interval of input values.
• The average rate of change of a function f from $x = x_1$ to $x = x_2$ is the constant rate of change of a linear function g that has the same change in output values as the function $f$ over the interval $[x_1, x_2]$.