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anonymous

  • one year ago

Find P(X <= k) in each case: a) n=20, p=0.05, k=2 b) n=15, p=0.7, k=8 c) n=10, p=0.9, k=9 Please help! I don't need the answers, I just need to know how to do the questions.

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  1. anonymous
    • one year ago
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    plug in the given values into the appropriate place

  2. anonymous
    • one year ago
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    what given space?

  3. anonymous
    • one year ago
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    given values

  4. anonymous
    • one year ago
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    im confused, plug them into what?

  5. anonymous
    • one year ago
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    what type of calculator do you have?

  6. anonymous
    • one year ago
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    a scientific one

  7. anonymous
    • one year ago
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    sharp EL-W535X

  8. anonymous
    • one year ago
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    okay well whats the formula i would use on paper if i was to do it by hand?

  9. anonymous
    • one year ago
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    what class is this for?

  10. anonymous
    • one year ago
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    statistics for the sciences

  11. anonymous
    • one year ago
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    yeah

  12. anonymous
    • one year ago
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    so what do i do?

  13. anonymous
    • one year ago
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    P(X≤k) = P(X=0) + P(X=1) + ...+ P(X=k)

  14. anonymous
    • one year ago
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    does that look familiar?

  15. anonymous
    • one year ago
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    yeah i know how to do that but am i really supposed to do that all the way up to 20?

  16. anonymous
    • one year ago
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    well im doing this on paper i guess i can show my work for the first one and write P(x=2) +--->P(x=20) = ?

  17. anonymous
    • one year ago
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    you think that would be okay?

  18. anonymous
    • one year ago
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    i have no idea, depends on what your teacher wants

  19. anonymous
    • one year ago
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    im not sure tbh well if theres a faster way i think it would be better to do it that way bc atleast all my work will be shown

  20. anonymous
    • one year ago
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    do you have a binomcdf function on your calculator?

  21. anonymous
    • one year ago
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    i have no idea

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  22. anonymous
    • one year ago
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    Just a quick tip, for the last one, instead of doing P(x=0) all the way up to P(x=9), you can just do 1 - P(x = 10). I think you can use a similar method for the 2nd part. Either do that or just use your calculator like you've been saying :P

  23. anonymous
    • one year ago
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    i dont know how to calculate this question

  24. anonymous
    • one year ago
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    JE so for part a can i do 1 - P(x=20)? to get the answer?

  25. anonymous
    • one year ago
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    No, for part a you should just do P(x=0) + P(x=1) + P(x=2)

  26. anonymous
    • one year ago
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    If you find for any question like this you have to sum a load of things then it might be better to do 1 - the things that aren't in the sum, just to simplify calculations.

  27. anonymous
    • one year ago
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    but why cant i do this for part a?

  28. anonymous
    • one year ago
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    You could, but you'd be doing 1 - P(x=20) - P(x=19) - P(x=18) - P(x=17) - ... - P(x=3) which is a lot of calculation. It's much easier in this case to do P(x=0) + P(x=1) + P(x=2).

  29. anonymous
    • one year ago
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    all the way up to 20?

  30. anonymous
    • one year ago
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    No, just up to 2. If you're calculating P(x<=k) then you sum from 0 to k, since x can only take the values 0, 1, 2, 3, ..., k if it is <=k.

  31. anonymous
    • one year ago
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    Like on that other question, you can use P(x<=k) = 1-P(x>k) if it makes the calculations easier, which is very useful for the last part!

  32. anonymous
    • one year ago
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    okay so i do P(x=0) + P(x=1) + P(x=2) and then - 1?

  33. anonymous
    • one year ago
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    You don't need the -1 but yes. Essentially you're doing P(x <= 2), so this means x can only take the values 0, 1, 2. You'd only need to do 1 - (stuff) if you were trying to calculate P(x > 2).

  34. anonymous
    • one year ago
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    okay so i just add up P(x=0) + P(x=1) + P(x=2) to get the answer for a?

  35. anonymous
    • one year ago
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    Yes :)

  36. anonymous
    • one year ago
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    okay I got 0.924 for a)

  37. anonymous
    • one year ago
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    how about for b and c the k values are pretty high

  38. anonymous
    • one year ago
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    For b I think you're just going to have to add up all the stuff again; but as billj5 was saying your calculator might have a function to calculate P(x<=8) for you, if you know about it.

  39. anonymous
    • one year ago
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    i dont :(

  40. anonymous
    • one year ago
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    Ah well you may just have to do the sum :P Maybe ask someone who you can show your calculator to if it has this function?

  41. anonymous
    • one year ago
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    okay well thank you again JE!

  42. anonymous
    • one year ago
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    You're welcome :)

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