Hello all,
I would like to compare the means and SDs of 3 groups.
The only data I have are sample size, mean, and SD for each group as presented below:
Group 1 : sample size 1: 250 mean 1: 1.95 SD 1: 0.46
Group 2: sample size 2: 250 mean 2: 2.54 SD 2: 0.43
Group 3: sample size 3: 250 mean 3: 2.72 SD 3: 0.60
Which test of significance should I used and how can I compare the 3 groups in Stata?
Thank you and best wishes.
I think you can use the Coefficient of Variation (CV), which is the ratio between the standard deviation and the mean value. CV measures the amount of variation to the mean. It is not a good idea to compare means when they have entirely different variances. In these situations, CV will be a good measurement to use.
Please follow this link (https://cran.r-project.org/web/packages/cvequality/vignettes/how_to_test_CVs.html), which discusses how to compare CVs values. I hope this will help you.
search aovsum // Install it if necessary
aovsum, ///
n(250 250 250) ///
m(1.95 2.54 2.72) ///
sd(0.46 0.43 0.60)
HTH.
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