Can someone please help me, I have been working on this for 2 hours now and I keep getting a negative answer.

Question

You are given the following data.
Number of Absences Final
Grade
0 99
1 94
2 79
3 73
4 68
5 53


- Find the correlation coefficient for the data.
- Find the equation for the regression line for the data, and predict the final grade of a student who misses 3.5 days.

Answer 1

Using an online calculator, I have the following data:

6 data pairs (x,y):
( 0.00 , 99.0 ); ( 1.00 , 94.0 ); ( 2.00 , 79.0 ); ( 3.00 , 73.0 ); ( 4.00 , 68.0 ); ( 5.00 , 53.0 );

y = a + bx where:
a= 100
b= -8.97

r = -0.986

In the regression equation, substitute 3.5 for x and solve for y to predict the final grade.

I hope this helps.