Discuss what assumption(s) is necessary to make the POLVIEWS spectrum responses an interval variable.

If we interpret the responses to POLVIEWS (1 = Extremely liberal, 2 = Liberal, 3 = Slightly liberal, 4 = Moderate, 5 = Slightly conservative, 6 = Conservative, 7 = Extremely conservative) as an interval variable we can acquire useful information about where people stand on the liberal–conservative spectrum.