Aresearcher decides to use the experimental method to see the effectiveness of a new teaching method on the achievement scores of subjects. Two groups are formed, that is, the experimental group (those who receive training using the new teaching method) and the control group

(those who receive training using the usual method). After six months, an achievement test is administered on the subjects in the two groups. The scores on the test range from 0 to 100.What scale of measurement is used to measure the achievement scores of the subjects? Why?