Math · 3

In a classic Simpson's Paradox case like hospital survival-rate data, what can happen even though Treatment A outperforms Treatment B in every individual subgroup?

Answer

Treatment B can appear to outperform Treatment A once the subgroups are combined into an overall total

Simpson's Paradox shows that aggregating subgroup data can mask the true relationship, allowing the overall combined result to contradict every individual subgroup outcome, typically because subgroup sizes differ unevenly.

💡 Did you know?

The Simpson's Paradox flips outcomes: Treatment A beats B in every subgroup, yet B wins overall—a real phenomenon hospitals face with survival rate statistics.

Other options people guess

  • Treatment A must still outperform Treatment B in the combined overall total
  • The subgroup results are statistically invalid and must be discarded
  • The reversal can only occur if the subgroups happen to be equal in size

Topics

  • probability
  • statistics
  • paradox
  • counterintuitive

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