Data was collected on the amount of time that a random sample of 8 students spent studying for a test and the grades they earned on the test. A scatter plot and line of fit were created for the data. Find the slope of the line of fit and explain its meaning in the context of the data.

80; a student who studies for 0 hours is predicted to earn 80% on the test 60; a student who studies for 0 hours is predicted to earn 60% on the test 10; for each additional hour a student studies, their grade is predicted to increase by 10% on the test 5; for each additional hour a student studies, their grade is predicted to increase by 5% on the test