I want an explanation for this example

3. A professor wants to research about correlation between their students' performance and time spent on watching web-series. The professor asked 7 students about how many hours per week they spent on watching web-series and their grades in the last test.

Following plot indicates the findings of this survey.

100 90 +.... . ........ y = -3.7191x + 97.011 80 R2 = 0.9431 70 ..4. . . 60 50 ............... % on test 40 30 20 10 0 O 2 4 6 8 10 12 14 Weekly hours spent on watching webseries