Question

how much higher was russells score when he studied for 80 minutes than when he studied for 20 minutes?

Explanation:

Step1: Find score at 80 mins

From the scatter plot, when study time is 80 minutes, the score is 90.

Step2: Find score at 20 mins

From the scatter plot, when study time is 20 minutes, the score is 70.

Step3: Calculate the difference

Subtract the two scores: $90 - 70$

Answer:

20