3 ms·

Which is why units should be randomly selected into each groups to avoid confounding factors like the one you mention.

• wiml 10y ago
  Ah, but a person with preëxisting good luck might be preferentially randomly selected into the nose-touching group, amplifying the effect and making it hard to measure its size.
  • wruza 10y ago
    You throw out min/max results anyway before analyzis.