Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

yashar806

Weights of apples grown in an orchard are known to follow a normal distribution with mean 160 grams. It is known that approximately 99.7% of apples have weights between124 and 196 grams. What is the standard deviation of weights of all apples grown in the orchard?

  • one year ago
  • one year ago

  • This Question is Closed
  1. tomo
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1363376606947:dw|

    • one year ago
  2. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    but i cant get the right answer

    • one year ago
  3. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    i used that that formula

    • one year ago
  4. tomo
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1363376747863:dw|

    • one year ago
  5. tomo
    Best Response
    You've already chosen the best response.
    Medals 0

    z1 = (124-160)/sigma z2 = (196-160)/sigma 1-z1-z2 = (99.7)/100

    • one year ago
  6. tomo
    Best Response
    You've already chosen the best response.
    Medals 0

    i have to leave, but I think that should help you find the answer

    • one year ago
  7. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    dont we just need one of those to determine sigma?

    • one year ago
  8. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    \[z=\frac{x-\bar x}{sd}\] \[sd=\frac{x-\bar x}{z}\]

    • one year ago
  9. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    i got confused

    • one year ago
  10. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    why we need to 1- them

    • one year ago
  11. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    or rather, we dont have the z value explicitly do we

    • one year ago
  12. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    we do have z

    • one year ago
  13. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    99.7%

    • one year ago
  14. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1363377005023:dw|

    • one year ago
  15. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    we have an implicit z, we can either use the zscore of .3/2 .. or 99.7+.3/2

    • one year ago
  16. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    what would be answer?

    • one year ago
  17. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    does that make sense? 99.7% is inbetween those values, so the proper zscore has to be adjusted. use z(.9985), at x=196 or, z(.0015), at x=124

    • one year ago
  18. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

    • one year ago
  19. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    id prolly use the 196 version

    • one year ago
  20. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    can you tell me the zscore of .9985?

    • one year ago
  21. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    2.96

    • one year ago
  22. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    i agree soo, sd= (196-160)/2.96

    • one year ago
  23. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    oh, i got it

    • one year ago
  24. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    can we use both of them?

    • one year ago
  25. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    both of what?

    • one year ago
  26. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    z1 = (124-160)/sigma z2 = (196-160)/sigma

    • one year ago
  27. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    like that

    • one year ago
  28. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    we can, the sd will be negative for the z1 equation and the percentage at z1 is (.0015), iinstead of (.9985)

    • one year ago
  29. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    thats wht i used initially

    • one year ago
  30. yashar806
    Best Response
    You've already chosen the best response.
    Medals 0

    but i got wrong answer

    • one year ago
  31. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    one chk would be to do (124-160)/12.1622 and see if its about -.0015 :)

    • one year ago
  32. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    hmm, i get -2.96 is 160 by chance the average of 124 and 196?

    • one year ago
  33. amistre64
    Best Response
    You've already chosen the best response.
    Medals 0

    .... yep

    • one year ago
    • Attachments:

See more questions >>>

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.