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radh

  • 3 years ago

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  1. radh
    • 3 years ago
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    Grades can be converted into numbers (as in calculating a GPA) where an A = 4, B = 3, C = 2, D = 1, and F = 0. For a fictional class, the grade distribution was: X(Grade) 4 3 2 1 0 P(X) 0.20 0.25 0.30 0.10 0.15 a) Verify that this is a legitimate probability distribution. b) Find the mean grade for this class. c) Find the standard deviation

  2. lilfayfay
    • 3 years ago
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    wrong section

  3. radh
    • 3 years ago
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    openstudy has a stats section?

  4. hartnn
    • 3 years ago
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    could u do part a) ?

  5. lilfayfay
    • 3 years ago
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    yeah

  6. lilfayfay
    • 3 years ago
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    at the top it will say "Find More Subjects"

  7. radh
    • 3 years ago
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    yeah, I know part a. It's legitimate because the total probability is equal to 1.

  8. hartnn
    • 3 years ago
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    good, thats correct. where r u stuck ?

  9. lilfayfay
    • 3 years ago
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    Yeah its at the very bottom if you click on "Find More Subjects" at the top :))

  10. radh
    • 3 years ago
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    finding the mean/sd. i found those out, but idk how to corrleate them with the grades. i know mean is .2, so would that mean the average grade is 4 because its' probability is .2?

  11. radh
    • 3 years ago
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    oh, whoops. i didn't see that before. i'll go there next time.

  12. hartnn
    • 3 years ago
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    mean is 0.2 ? which formula did u use ?

  13. radh
    • 3 years ago
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    total is 1, divided by 5, .2? did i do that wrong?

  14. hartnn
    • 3 years ago
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    yes... Mean = \(\sum xP(x)\) so, it will be mean = 0.2*4 + 0.25*3 + ......

  15. radh
    • 3 years ago
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    oooh. okay. one sec. let me calculate that. :P

  16. radh
    • 3 years ago
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    2.25?

  17. hartnn
    • 3 years ago
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    don't u have answers to verify ?

  18. hartnn
    • 3 years ago
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    yeah, even i get 2.25

  19. radh
    • 3 years ago
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    nope. answers are given upon completion. :P

  20. radh
    • 3 years ago
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    but thanks, I think I got it now. Wrong formula. :P

  21. hartnn
    • 3 years ago
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    and u know formula for sd ?

  22. radh
    • 3 years ago
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    yeah, got that. i compared that with a friend, and she got the same answer. it was just the mean.

  23. hartnn
    • 3 years ago
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    ok, good :)

  24. hanban1
    • 3 years ago
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    hartnn, if you don't mind could you explain how to find the standar deviation, i'm a bit confused on how to go about it.

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