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chocolatechip_543

  • 2 years ago

The following table shows the probability distribution for a discrete random variable. X 13 16 18 21 23 25 26 31 P(X) 0.07 0.21 0.17 0.25 0.05 0.04 0.13 0.08 The mean of the discrete random variable X is 20.59. What is the variance of X? Round your answer to the nearest hundredth.

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  1. telliott99
    • 2 years ago
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    http://math.elon.edu/statistics112/prob_dist.html

  2. hal_stirrup
    • 2 years ago
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    \[s2 = Σ ( x _{I} - x )2 / ( n - 1 )\]

  3. hal_stirrup
    • 2 years ago
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    are you there??

  4. chocolatechip_543
    • 2 years ago
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    yes

  5. chocolatechip_543
    • 2 years ago
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    can you explain the equation a bit?

  6. hal_stirrup
    • 2 years ago
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    sure lets star with \[\sum_{i=1}^{n}\]

  7. hal_stirrup
    • 2 years ago
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    do you understand what this means?

  8. chocolatechip_543
    • 2 years ago
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    yes

  9. hal_stirrup
    • 2 years ago
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    good then\[x_{i} -x\] xi is each value of your x value . -x really i cant use xbar because the keyboard is limited .. x bar is the average= \[xbar=\sum_{i=1} x _{i}/n\]

  10. hal_stirrup
    • 2 years ago
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    we are assuming that you have sample and not population as well !!!!

  11. chocolatechip_543
    • 2 years ago
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    alright..I'm a little lost now

  12. hal_stirrup
    • 2 years ago
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    tell me where.

  13. chocolatechip_543
    • 2 years ago
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    at the last part you posted

  14. hal_stirrup
    • 2 years ago
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    "we are assuming that you have sample and not population as well" that

  15. chocolatechip_543
    • 2 years ago
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    yes and before that

  16. hal_stirrup
    • 2 years ago
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    look. inorder to help you you need to be clear as to where are you not understanding . so i can help you better. thanks

  17. chocolatechip_543
    • 2 years ago
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    I'm sorry, I just don't understand it.

  18. hal_stirrup
    • 2 years ago
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    no need to be sorry . :)

  19. hal_stirrup
    • 2 years ago
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    have you done statistics before ?

  20. chocolatechip_543
    • 2 years ago
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    no, but this is in my algebra 2 work

  21. hal_stirrup
    • 2 years ago
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    thats cool/

  22. hal_stirrup
    • 2 years ago
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    do you now how to get the mean?

  23. chocolatechip_543
    • 2 years ago
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    yes

  24. hal_stirrup
    • 2 years ago
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    ok so were half way.

  25. hal_stirrup
    • 2 years ago
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    lets talk concept first. is that ok?

  26. chocolatechip_543
    • 2 years ago
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    sure

  27. hal_stirrup
    • 2 years ago
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    variance is the distance from the mean measured in squares. |dw:1343956195413:dw|

  28. hal_stirrup
    • 2 years ago
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    in you r case you have many data points. so really your job is fine all the distance from the mean and then sum them up and divide by the number of data point and minus 1.

  29. hal_stirrup
    • 2 years ago
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    s2=Σ(xI−x)2/(n−1) thats what this formula say.

  30. chocolatechip_543
    • 2 years ago
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    oh alright

  31. hal_stirrup
    • 2 years ago
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    share what your thinking if you like?

  32. hal_stirrup
    • 2 years ago
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    if you like to , be my fan and send my question and thoughts if you want and dont forget to click on best response . thanks @chocolatechip_543

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