In a classic study by V.O. Key in the 1950s, differences in political opinion were closely associated with: September 08, 2018 Public Opinion In a classic study by V.O. Key in the 1950s, differences in political opinion were closely associated with: a. occupation. b. race. c. gender. d. ethnicity. e. education levels. Answer: a Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+