+ Reply to Thread
Results 1 to 1 of 1

Thread: How to combine standard deviations for paired samples?

  1. #1
    Points: 4, Level: 1
    Level completed: 7%, Points required for next Level: 46

    Posts
    1
    Thanks
    0
    Thanked 0 Times in 0 Posts

    How to combine standard deviations for paired samples?




    I have a group of individuals X, each member of the group has had two measures taken: i and j.

    I have the means and SDs of i and j. I also know the correlation coefficient between i and j: r.

    I am able to calculate the combined mean of i and j: k

    How do I calculate the standard deviation of k? The formula I have for combining SD, is for separate populations and therefore overestimates the SD (picture attached).


    Many thanks for your help,

    Rob
    Attached Images  

+ 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