4-13. Students in a management science class have just received their grades on the first test. The instructor has provided information about the first test grades in some previous classes as well as the final average for the same students. Some of these grades have been sampled and are as follows:
Student 1st test grade Final average
1 98 93
2 77 78
3 88 84
4 80 73
5 96 84
6 61 64
7 66 64
8 95 95
9 69 76
a)Develop a regression mode that could be used to predict the final average in the course based on the first grade.
b)Predict the final average of a student who made an 83 on the first test.
c) Give the value of r and r squared for this model. Interpret the value of r squared in the context of this problem.