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← 28-03 Survey

28-03 Survey

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Showing Revision 2 created 11/02/2015 by Udacity Robot.

  1. Consider a website with 100,000 users.
  2. A thousand of those are highly active, and you want to take a survey.
  3. Now, to simplify this, let's assume that you draw the users at random
  4. and that everyone responds.
  5. If you send out 10 surveys, I'd like you to tell me the probability
  6. that the number of highly active users in our sample is greater than or equal to 2.
  7. We have at least two of our highly actives in our sample of 10 surveys.
  8. Now, remember that sometimes it may be easier to compute the probability
  9. of something being less than a given number,
  10. and you can take 1 minus that and that is always going to be equal,
  11. since the probabilities always have to add up to 1.
  12. Enter your answer here.