A psychologist collects data on the time, w, in minutes, people walk each day and their scores, t ,on a stress test. The scores are from 0 to 100, with higher scores meaning more stress. She finds that there is a negative linear association between w and t that is best modeled by the equation t=−2.5w+48.1 .
What is the meaning of 48.1 in this equation?
A. The people who walked each day had an average score of 48.1 on the stress test.
B. The model predicts that a person who does not walk each day will score about 48.1 on the test.
C. The people in the study walked an average of 48.1 minutes each day.
D. For each additional minute spent walking, the model predicts that a person's score on the stress test will go down by about 48.1 points.