+ Reply to Thread
Results 1 to 4 of 4

Thread: A little guideance needed...

  1. #1
    Points: 30, Level: 1
    Level completed: 60%, Points required for next Level: 20

    Posts
    6
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Unhappy A little guideance needed...




    First off, I hoped I've posted in the right forum-if not sorry xx

    I'm working through a sample question regarding a sample of 20 sections of interior pipe and having found the following

    mean=1.881
    Variance=0.274483158
    st dev=0.5239114028

    I've struggled with the second part b, "Construct and interpret a 95% confidence interval for the mean surface roughness of coated interior pipe. "

    Any advice would be extremely grateful, thank you

  2. #2
    Fortran must die
    Points: 58,790, Level: 100
    Level completed: 0%, Points required for next Level: 0
    noetsi's Avatar
    Posts
    6,532
    Thanks
    692
    Thanked 915 Times in 874 Posts

    Re: A little guideance needed...

    The policy is to provide advice to these type of questions not answers.

    You n=20
    Your SD= .5239..
    Mean = 1.881
    Your t value will be found in a table for the given n above and you 95% Cl


    http://www.dummies.com/how-to/conten...r-a-popu0.html

    You will use a t not z value because n<30 (and because
    "Very few theories have been abandoned because they were found to be invalid on the basis of empirical evidence...." Spanos, 1995

  3. The Following User Says Thank You to noetsi For This Useful Post:

    JesperHP (07-29-2013)

  4. #3
    Super Moderator
    Points: 31,766, Level: 100
    Level completed: 0%, Points required for next Level: 0
    bugman's Avatar
    Posts
    2,255
    Thanks
    290
    Thanked 324 Times in 265 Posts

    Re: A little guideance needed...

    Becasue what noetsi? I have been waiting for hours...
    The earth is round: P<0.05

  5. #4
    Points: 30, Level: 1
    Level completed: 60%, Points required for next Level: 20

    Posts
    6
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Re: A little guideance needed...


    ha ha, nice one bugman- thank you Noetsi

+ Reply to Thread

           




Posting Permissions

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






Advertise on Talk Stats