I need an explanation of this example.

In a research project to determine the relationship between the number of test review problems solved and students' grades for the test, 6 students were randomly chosen and below data was collected

x (number of review problems solved)	y (students grades in %)
10	82
12	85
5	45
9	83
15	87
11	86

a) Draw a scatter plot for the data;

b) Find the equation of the line of best fit. Draw the line of best fit on the scatter plot diagram. Round off the coefficients to one decimal place; show all calculations.

c) Find the coefficient of determination. Write a statement of interpretation for it.