3 ms·

sounds expensive. 0.01 may be more reasonable.

• mrob 9y ago
  Choosing the correct value is a social problem. Eg. The Journal of Wacky Speculation publishes "The Moon is Made of Green Cheese". Using a highly sophisticated cheese detector, the authors measure results consistent with this hypothesis. They calculate it would happen only 4% of the time if the moon were not in fact made of green cheese, and therefore the result is significant. The cheese detector works perfectly, the calculations were accurate, but this does not mean the moon is made of green cheese! We've been there, and we're very certain that it's made of rock. Because the prior probability of the hypothesis was so low, the "significant" result was most likely a fluke. The Journal of Wacky Speculation specializes in this type of hypothesis, so they should use a much lower threshold for p. Meanwhile, the Sensible and Boring Society publishes a study showing that round wheels roll better on ordinary roads than square wheels. We already had good reason to believe this, so p<0.05 shows it's most likely true. The Sensible and Boring Society publishes tests of hypotheses with higher prior probably, so they can use a higher p threshold.