2012年11月7日, Matt Bai, “Winning a Second Term, Obama Will Confront Familiar Headwinds”, 出自 New York Times [紐約時報][1]:
In polling by the Pew Research Center in November 2008, fully half the respondents thought the two parties would cooperate more in the coming year, versus only 36 percent who thought the climate would grow more adversarial.
2005, Robert E. Weiss, Modeling Longitudinal Data, Springer, →ISBN,第 104 頁:
If, for example, we select random people entering a workout gym, versus if we pick random people entering a hospital, we will get very different samples.