Classify the following as quantitative or qualitative variables.
(a) Gender
(b) Brand of soft drink
(c) Race (classified as white or non-white)
(d) US trade deficit with China
(e) Price index
(f) Price of Gold
(g) Exchange rate between $ and e
(h) Military rank
(i) The US money supply
(j) Energy use per e1 of GDP of EU members
(k) Farm productivity in developing countries
(l) Average manufacturing unit labor costs of G7 countries
(m) Federal grant to 50 states in 2012
(n) Real private fixed investment
(o) Number of spectators in a 90,000 seats stadium
(p) Population of NAFTA countries in the last 20 years
(q) Money supply of OECD countries in 2012
(r) Inflation rate of Latin American countries for the last 10 years
(s) Closing prices of stocks of companies in S&P 500 index
(t) Employment status of a person in the work force
(u) Religion (classified as Christian or non-Christian)
(v) Ethnicity (classified as Italian or non-Italian)
(w) Inflation rate of US major metropolitan areas in 2012