Quantcast

A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

mariomintchev

  • 2 years ago

Can someone explain the STANDARD DEVIATION OF THE DIFFERENCES formula to me?

  • This Question is Closed
  1. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @jagatuba @Jemurray3 @jhonyy9 @karatechopper @phi @robtobey @satellite73

  2. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I am given 2 sets of 10 numbers. How do I plug them into this formula to get the correct answer?

  3. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    so what numbers you have got for ????

  4. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    1 Attachment
  5. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    the sum across the values how you can get it ?

  6. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    im confused about the top part of the formula. ive been getting the wrong answers so i must be doing something wrong.

  7. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    sorry but this attachement i not can opening ,not id compatibly with my excell programm

  8. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    1 Attachment
  9. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    what about now?

  10. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    can you rewrite me here the values for x and X the mean or average and the value for n ?

  11. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    @robtobey can you opening this attachement please ?

  12. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    (column 1) x = 129, 237, 110, 32, 322, 134, 119, 32, 172, 149 total sum for x = 1436 mean for x = 143.6 (column 2) y = 130, 224, 113, 38, 320, 124, 122, 33, 169, 148 total sum for y = 1421 mean for y = 142.1 value for n = 10 df = n-1 (so 9)

  13. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    have you any idea for this ?

  14. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yes but ive been getting the wrong answers. d bar = 1.5 so ive been doing ((129-1.5)^2+(237-1.5)^2+(110-1.5)^2+.......))

  15. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    so how i see it there will be in numerator sqrt(sum(x-X)^2) divide by sqrt9 so divide by 3 ok ?

  16. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    can you calcule first this sum ?

  17. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    how many will be this sum ?

  18. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    i got 270258.5 for x and 261262.5 for y then i subtracted the 2 to get 8996

  19. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    then divide by 9 and square root it to get 31.616

  20. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    but thats wrong

  21. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    why divide by 9 and not by 3 ?

  22. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    arent u supposed to do whats in the radical first and then square root it?

  23. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    why you can separte it sqrt of numerator and sqrt of denominator and vide it after

  24. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    and divide it after

  25. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    i get the same answer either way

  26. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    31.616

  27. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    the right answer is 5.93

  28. robtobey
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @jhonyy9 It may to late for solving this problem. Attached is a screen capture of part of the xls file. I am running on a mid 2010 IMac with 8Gb of ram to support virtual versions of Windows XP pro, Windows 98SE and in the past Ubuntu Linux. The xls file is not a normal spread sheet data file. All I can provide is a screen capture of what I see.

    1 Attachment
  29. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    how can i opening it what program i need using for ?

  30. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    i provided all the necessary info above ^^^^^

  31. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    so than you need calcule right this sum and after make the squareroot of them ,yes ?

  32. jhonyy9
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    so and after just divide it by 3

  33. robtobey
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Ask @mariomintchev what version of Excel did she/he use to generate the spread sheet.

  34. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Excel 2010

  35. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    SCREENSHOT

  36. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    They want the standard deviation of the differences. Your formula tells you how to find the standard deviation of a list of numbers. The first step is find the list of numbers: the list of differences so find x-y where x= 129, 237, 110, 32, 322, 134, 119, 32, 172, 149 y = 130, 224, 113, 38, 320, 124, 122, 33, 169, 148 the differences (call it z) are z= -1 13 -3 -6 2 10 -3 -1 3 1 now use your formula to find the standard deviation

  37. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    so ((-1-1.5)^2+(13-1.5)^2+(-3-1.5)^2+....)) ???

  38. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yes, then divide by 9 then take the square root.

  39. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    ok, i got 5.95 so its close enough. thanks phi, i can always rely on you!

  40. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I got 5.930 (dd-1.5).^2 6.2500 132.2500 20.2500 56.2500 0.2500 72.2500 20.2500 6.2500 2.2500 0.2500 sum(ans)/9 = 35.1667 sqrt(35.1667)= 5.9302

  41. mariomintchev
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 1

    i must have made a little mistake somewhere when punching in all of those numbers and parenthesis. i understand what i need to do now though. thanks! =o)

  42. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.