Page 5 of 5 FirstFirst ... 345
Results 101 to 123 of 123
Like Tree21Likes

Thread: University Statistics Discussion Marathon

  1. #101
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Id rule out A straight up as well, which would love me down to B or C.
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  2. #102
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Statistical validity refers to whether a statistical study is able to draw conclusions that are in agreement with statistical and scientific laws. This means if a conclusion is drawn from a given data set after experimentation, it is said to be scientifically valid if the conclusion drawn from the experiment is scientific and relies on mathematical and statistical laws.

    id also refer out C, and would go for B in this question.
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  3. #103
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  4. #104
    Ancient Orator
    Join Date
    Dec 2014
    HSC
    N/A
    Gender
    Male
    Posts
    5,678
    Rep Power
    5

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by davidgoes4wce View Post
    Third option

  5. #105
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Damn I would have gone for 4th..........
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  6. #106
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    any idea how you would explain it?





    I don't see how you then can get to n-1
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  7. #107
    Ancient Orator
    Join Date
    Dec 2014
    HSC
    N/A
    Gender
    Male
    Posts
    5,678
    Rep Power
    5

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by davidgoes4wce View Post
    any idea how you would explain it?





    I don't see how you then can get to n-1

  8. #108
    Ancient Orator
    Join Date
    Dec 2014
    HSC
    N/A
    Gender
    Male
    Posts
    5,678
    Rep Power
    5

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by davidgoes4wce View Post
    Damn I would have gone for 4th..........

  9. #109
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    The company Atherton uses a particular machine to fill 1 kg bags with sugar. The weight X of the machine processed bags follows a normal distribution with mean and standard deviation =0.24. The machine mean weight can be set by the operator to any value between 0 kg and 50 kg. Regulations allow to sell sugar bags as "1 kg bags" if at least 97.5% of the production is 1 kg or heavier. Answer the following question, round off the final results to 2 dp, but without rounding numbers during your calculations.

    What mean weight should the machine be set to in order to produce 97.5% of the bags weighting at least 1kg?
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  10. #110
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Anyway I had a go at. If someone could confirm that would be great.

    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  11. #111
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Doing Statistics on a Good Friday is insanely awesome.
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  12. #112
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Answer the following question, keeping in mind that your answer must be a number between 0 and 1, i.e do not use percentages. Round off the final results to 2d.p but dont round numbers during your calculation.

    Computer the probability that an observation 't' drawn from a normal distribution with mean = 24.1 and standard deviation is in the interval (15.05, 32.55) i.e the Prob (15.05 < t < 32.56) .
    Last edited by davidgoes4wce; 18 Apr 2017 at 12:07 AM.
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  13. #113
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Just want to confirm if this is the right answer :

    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  14. #114
    Ancient Orator
    Join Date
    Dec 2014
    HSC
    N/A
    Gender
    Male
    Posts
    5,678
    Rep Power
    5

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by davidgoes4wce View Post
    Just want to confirm if this is the right answer :

    davidgoes4wce likes this.

  15. #115
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    50 % of the meals sold at Graylands Hospital contain rice.

    Answer the following question, keeping in mind that your answer must be a number between 0 and 1, i.e do not use percentages. Round off the final result to 2dp, but don't round numbers during your calculations.

    What is the probability that out of 78 meals sold at Graylands Hospital, 43 or more contain rice?
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  16. #116
    Junior Member
    Join Date
    Sep 2016
    HSC
    N/A
    Gender
    Undisclosed
    Posts
    188
    Rep Power
    1

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by davidgoes4wce View Post
    50 % of the meals sold at Graylands Hospital contain rice.

    Answer the following question, keeping in mind that your answer must be a number between 0 and 1, i.e do not use percentages. Round off the final result to 2dp, but don't round numbers during your calculations.

    What is the probability that out of 78 meals sold at Graylands Hospital, 43 or more contain rice?

    Not sure... how to compute... (p = 0.5)

    Last edited by He-Mann; 21 Apr 2017 at 12:36 AM.

  17. #117
    Executive Member
    Join Date
    Jun 2014
    HSC
    N/A
    Gender
    Male
    Location
    Sydney, New South Wales
    Posts
    1,880
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by He-Mann View Post
    Not sure... how to compute... (p = 0.5)

    what value of p did you get?
    | B Eng (Hons) | IB Mathematics SL | IB Mathematics HL | Australian Cricket | Casual University Statistics Tutor

  18. #118
    Ancient Orator
    Join Date
    Dec 2014
    HSC
    N/A
    Gender
    Male
    Posts
    5,678
    Rep Power
    5

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by davidgoes4wce View Post
    what value of p did you get?
    Do you mean the value of the sum? (The "p" He-Mann used was referring to the success probability parameter, which is 0.5.)
    kawaiipotato and He-Mann like this.

  19. #119
    Junior Member
    Join Date
    Sep 2016
    HSC
    N/A
    Gender
    Undisclosed
    Posts
    188
    Rep Power
    1

    Re: University Statistics Discussion Marathon

    Can't any quick way of doing it at the moment. Please let me know if any of this is wrong.



    Since probabilities sum to 1, we have



    By symmetry (i.e. Pascal's Triangle), we have



    Then from (*), we have



    Now, we compute the desired probability,



    In retrospect, I should have wrote p = 0.5 = 1 - p and combined the product which would make it easier to read.
    Last edited by He-Mann; 28 Apr 2017 at 9:13 PM.

  20. #120
    Junior Member
    Join Date
    Sep 2016
    HSC
    N/A
    Gender
    Undisclosed
    Posts
    188
    Rep Power
    1

    Re: University Statistics Discussion Marathon

    Bump! Really interested if someone has thought up of a more efficient way to do the question (or identify, if it exists, the flaws in my work).

  21. #121
    -insert title here- Paradoxica's Avatar
    Join Date
    Jun 2014
    HSC
    2016
    Gender
    Male
    Location
    Outside reality
    Posts
    2,354
    Rep Power
    4

    Re: University Statistics Discussion Marathon

    Mathematica 11 gives me 0.2141 from your initial sum...
    He-Mann likes this.
    If I am a conic section, then my e = ∞

    Just so we don't have this discussion in the future, my definition of the natural numbers includes 0.

  22. #122
    Ancient Orator
    Join Date
    Dec 2014
    HSC
    N/A
    Gender
    Male
    Posts
    5,678
    Rep Power
    5

    Re: University Statistics Discussion Marathon

    Quote Originally Posted by He-Mann View Post
    Can't any quick way of doing it at the moment. Please let me know if any of this is wrong.



    Since probabilities sum to 1, we have



    By symmetry (i.e. Pascal's Triangle), we have



    Then from (*), we have



    Now, we compute the desired probability,



    In retrospect, I should have wrote p = 0.5 = 1 - p and combined the product which would make it easier to read.
    Quote Originally Posted by He-Mann View Post
    Bump! Really interested if someone has thought up of a more efficient way to do the question (or identify, if it exists, the flaws in my work).
    Note that the answer to the sum cannot exceed 0.5 (in general for X ~ Bin(n, 1/2), if k > n/2, then Pr(X ≥ k) ≤ 0.5).
    Last edited by InteGrand; 27 Apr 2017 at 10:09 PM.
    He-Mann likes this.

  23. #123
    Junior Member
    Join Date
    Sep 2016
    HSC
    N/A
    Gender
    Undisclosed
    Posts
    188
    Rep Power
    1

    Re: University Statistics Discussion Marathon

    I have corrected my original working. Thanks for the checks, I knew something was strange.

    Below is an easier-to-read version.
    __________________________________________________ _________________________

    Given that p = 0.5 = 1-p,



    By Binomial Theorem (with x = 1) and Pascal's Triangle (i.e. C(n,k) = C(n, n-k)),



    Now, we compute the desired probability,

    Last edited by He-Mann; 28 Apr 2017 at 9:28 PM.

Page 5 of 5 FirstFirst ... 345

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •