+ Reply to Thread
Results 1 to 2 of 2

Thread: Statistical significance: T-test or something else? (Percentages from two samples)

  1. #1
    Points: 87, Level: 1
    Level completed: 74%, Points required for next Level: 13

    Posts
    10
    Thanks
    1
    Thanked 1 Time in 1 Post

    Question Statistical significance: T-test or something else? (Percentages from two samples)




    Hi guys,

    I have the following data and I want to show that the negative change for group 1 is statistically significantly different from the negative change for group 2. And along the same lines, I also want to compare positive change between group 1 and group 2.

    The number of observations is 312 for group 1 and 972 for group 2 and the means are in percentages. The percentages are obviously quite different - but how do I prove that they are statistically significantly different (ideally with p-values)?

    Key Indicator-----------First Group------------Second Group

    ------------------Observations---Mean-----Observations----Mean

    1 Grade change
    negative----------35-------------11,22%--------2--------------0,20%

    no change------149------------47,76%-------316-----------32,51%

    positive---------128-------------41,03%-------654-----------67,28%


    Is it possible to do a t-test here or what would you recommend?

  2. #2
    Points: 3,506, Level: 37
    Level completed: 4%, Points required for next Level: 144

    Posts
    129
    Thanks
    3
    Thanked 26 Times in 26 Posts

    Re: Statistical significance: T-test or something else? (Percentages from two samples


    I don't understand why you are calling these percentages "means". Aren't they just percentages? 35/312 = 0.112 (11.2%). That isn't the mean of anything.

    I would do a 2 (group) x 3 (change type) chi-square. I could also see dropping the non-changes and doing a 2x2 chi-square to see if, among those who changed, the pattern differed. I think it will be highly significant either way.

+ 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