Answer:
A.) ŷ = 0.73986X + 18.98921
B.) 80
C.) r = 0.9205
Step-by-step explanation:
Given :
1st test grade (X) :
98
77
88
80
96
61
66
95
69
final average (Y) :
93
78
84
73
84
64
64
95
76
Using a linear regression calculator :
The model obtained is :
ŷ = 0.73986X + 18.98921
Student with x = 83
ŷ = 0.73986(83) + 18.98921
ŷ = 80.39759
ŷ = 80 (nearest whole number)
The R value is : 0.9205 which shows that there is a strong linear correlation between the first test grade and the final average a student Obtian in an exam because the r value is very close to 1.
R² = √0.9205 = 0.8473 ; this means about 84.73% of variation in final average can be explained by the regression line.