+ Reply to Thread
Results 1 to 2 of 2

Thread: Confidence interval question

  1. #1
    Points: 60, Level: 1
    Level completed: 20%, Points required for next Level: 40

    Posts
    3
    Thanks
    0
    Thanked 0 Times in 0 Posts

    Confidence interval question




    Fr a sample of 100 hypertensive patients, we find that a 95% confidence interval of systolic BP to be [130, 150]. What statement is FALSE?

    A- if a drug is given that makes the patients BP more variable, then the resulting CI of the post-treatment BP will be wider.

    B-A 90% CI of the BP based on the same data will be narrower.

    C-If a drug is given to exactly reduce the BP by 10 units in every patient, then the CI post Treatment will be narrower.

    D-A 95% CI on a random subset of 60 patients is going to be wider.


    I'm having trouble wrapping my head around this problem. I thought the answer was C, but now I'm questioning myself. Any thoughtS??

  2. #2
    TS Contributor
    Points: 17,749, Level: 84
    Level completed: 80%, Points required for next Level: 101
    Karabiner's Avatar
    Location
    FC Schalke 04, Germany
    Posts
    2,540
    Thanks
    56
    Thanked 639 Times in 601 Posts

    Re: Confidence interval question


    C tells you that the CI will be narrower if the mean blood pressure decreases by 10. You should perhaps check the formulas for the calculation of standard errors and CIs - is it the sample mean on which the width of the CI depends, or is it sample variance, or maybe both?

    With kind regards

    Karabiner

+ 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