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← Probability of Obtaining Mean - Intro to Descriptive Statistics

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Showing Revision 9 created 05/24/2016 by Udacity Robot.

  1. We know the z score, so we can find the probability of getting anything less
  2. than that z score using our z table. So here's 0.8 and here's the column where
  3. it intersects 0.04. So the probability of getting less than a mean of 40 is
  4. 0.7995. So the probability of getting greater than a mean of 40 is 1 minus
  5. 0.7995, which is only about 0.2. So it's somewhat unlikely to have randomly
  6. drawn a sample from the whole Klout population with a mean of 40. If this mean
  7. wasn't selected by chance, then it's possible that this app, the Bieber Tweeter,
  8. which automatically re-tweets Justin Bieber, could have played a role in
  9. increasing these people's Klout scores. But how unlikely is a probability of
  10. 0.2? There's no set threshold. But in the next lesson, we're going to show you
  11. how statisticians have formally decided whether or not something is likely or
  12. unlikely.