Simpson's paradox

That is, overall 70% of boys would be accepted compared with only 52% of girls, but the rates of acceptance from each group by type of course were identical.

Conversely, it may be the case that a drug trial seems to suggest, for a group as a whole, that the drug reduces mortality rates. However, when the data are stratified by gender, say, it may prove to be the case that the drug increases mortality rates for both genders. An example of such data is presented below.

Columns 2–4 suggest the drug trial was a success, reducing the mortality rate, while columns 5–7 and 8–10 show it was separately detrimental to both men and women. This paradox is possible here, as men and women have very different mortality rates, and the treated and control groups are not evenly distributed by gender. So, the seeming improvement only reflects that women treated with the drug have a better mortality rate than men who are untreated.

• Riemann, (Georg Friedrich) Bernhard
• Riemann hypothesis
• Riemannian manifold
• Riemann integral
• Riemann-Lebesgue lemma
• Riemann mapping theorem
• Riemann sphere
• Riemann surface
• Riemann zeta function
• Riemann–Roch Theorem
• Riesz representation theorem
• right angle
• right-angled triangle
• right-circular
• right derivative
• right-handed system
• right inverse
• right-regular
• rigid body
• rigid motion
• ring
• ring of integers
• rise
• risk
• Rn