Name: ______________________

Activity: Inference for Regression

1. Consider the following three data sets, where Row is the row number where the student sits in class, and Grade is the student’s grade in the course, using the usual 4 point scale.


 
SET #1
SET #2
SET #3
Row
Grade
Row
Grade
Row
Grade
1
4
1
2
1
4
2
2
2
4
2
3
4
3
4
0
4
2
6
0
6
1
6
1
7
1
7
3
7
0

 

(a)  Plot the data for each data set.
 
 
 
 
 
 
 
 
 
 
 
 
 
 


 

(b) Matching: Give the data set number associated with each of the following regression lines found using Minitab.  (Don’t calculate these equations.  Just use your vision and judgment.)  Then draw these lines on the corresponding graphs above.
 

     yhat = 4.46 - 0.615 x     Set # ___
 

     yhat = 2.46 - 0.115 x          Set # ___
 

     yhat = 4.00 - 0.500 x     Set # ___
 

(c)Which data set gives the strongest evidence of the claim that students who sit closer to the front tend to perform better? _____  Which data set provides the weakest evidence of this claim?  _____  OK – Now explain your reasoning!
 
 
 

(d) For each data set a test was done to see if there is a relationship between the row a student sits in and the student’s grade.  Minitab produced the following P-values.  Match these with the three data sets.
 

         .099         .001         .764