To measure whether test performance can be predicted based on one's anxiety, a researcher asked his students to come to the lab 15 minutes before they were to take an exam in his class. The researcher measured the students' heart rates and then matched these scores with their exam performance after they had taken the exam. Use the data below and SPSS to test whether heart rate can predict test performance in the population.

Student	Heart Rate	Exam Score
A	76	78
B	81	68
C	60	88
D	65	80
E	80	90
F	66	68
G	82	60
H	71	95
I	66	84
J	75	75
K	80	62
L	76	51
M	77	63
N	79	71

In this specific scenario, are the two variables of interest? Which is the IV and which is the DV? What is the scale of measurement for each variable?