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← 26-02 Raises_Solution

26-02 Raises_Solution

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

  1. And the answer for the µ‘ is 70,000 of this given salary increase and the new σ stays the same.
  2. We already talked about this example earlier in class, but now it's in the content
  3. of normal distribution so let me take a second to show this to you.
  4. In our normal, ignoring normalization constant,
  5. we know that everyone's salary is drawn from a distribution that looks like this.
  6. This is plugging in the mean and the variance as that defined it,
  7. and now we know, we set the new salary x' to be the old salary plus 10,000
  8. That is the same as saying that the old salary was the new salary minus 10,000.
  9. We now substitute this x over here with this expression over here--what we got is something
  10. that looks looks smallest, so you can see I took out the x and replaced it by x' minus 10,000
  11. and if you look at this carefully, you'll find this is the same as (x'-70,000)²/10,000².
  12. So that proves to you that the variance of the same deviation doesn't change
  13. and the mean has effect it by just increasing it to 70,000 but definitely
  14. the µ‘ is now 70,000 and the σ' remains 10,000.