t-test weird degrees of freedom
8 ビュー (過去 30 日間)
古いコメントを表示
Hi,
I did some t-test (two-tailed) and keeps geting weird degrees of freedom.
I have some pairs of vectors, all of size = [1 144], so n=144 observations for each group
ttest gave me the expected df (142) for some tests, but I also got 139 in another one, and even... 124 in an other one.
What is going on ? Why is the degree of freedom not 142 in all those tests ?
Thank you
1 件のコメント
Fatemeh Shomal Zadeh
2020 年 12 月 3 日
Hi,
Sorry, can you help me and explain how I can get DoF (degrees of freedom) from my test?
Thanks
採用された回答
Tom Lane
2012 年 6 月 6 日
I can think of two possibilities. First, if you have any NaN values, they are treated as missing and the df would be reduced accordingly. Second, if you ask for a test based on 'unequal' variances, the df is computed using a Satterthwaite approximation and may be a non-integer.
2 件のコメント
Fatemeh Shomal Zadeh
2020 年 12 月 3 日
Hi,
Sorry, can you help me and explain how I can get DoF (degrees of freedom) from my test?
Thanks
その他の回答 (0 件)
参考
カテゴリ
Help Center および File Exchange で Verification, Validation, and Test についてさらに検索
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!