PT 4 S1 Q23

Comments

• SSBM1000 Member

  September 2020 edited September 2020 614 karma

  Hello,

  Answer choice C is correct because we don't know the proportion of the population who have used cocaine. For all we know, only 10 people in the entire population have used cocaine, so we can't assume that the majority of those who test positive have used cocaine just because 99 percent of people who have used cocaine test positive, compared to 5 percent of people who haven't used cocaine. It completely neglects to take into account the total number of people who have used cocaine compared to people who haven't used cocaine, as if there is significantly less people who have used cocaine than people who haven't used cocaine, the conclusion in the stimulus can't be properly reached.

  B is wrong because it's descriptively inaccurate. The stimulus doesn't attribute to every member of a population the properties of an average member of the population, it just says that on average, those who test positive for cocaine are more likely to have used cocaine than not. The argument makes no generalization regarding the total population.
• 1 Like

  cthulhu14 Member

  September 2020 35 karma

  This helped a lot, thank you for the taking the time to type up an in-depth explanation!