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Talk:Welch–Satterthwaite equation

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Underlying normal?

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Some other statements[1] of the Welch–Satterthwaite equation state that the underlying distribution must be normal. I can also see mention of normality in the abstract of the referenced paper by Welch[2]. However, the article doesn't mention any constraints on the underlying distribution. Alex.sayers (talk) 09:26, 27 February 2018 (UTC)[reply]

References

Article is not very exact

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The following holds:

follows approximately a chi-square distribution with degrees of freedom.


k_i

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The article talks about which is nowhere defined. Can I take them arbitrary numbers? Frankmeulenaar (talk) 11:07, 19 April 2012 (UTC)[reply]

Yes. JMiall 12:22, 19 April 2012 (UTC)[reply]

nu

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The expression given has nu, which is nowhere referenced in the rest of the article. —Preceding unsigned comment added by 98.118.142.50 (talk) 20:25, 22 March 2011 (UTC)[reply]

"For n sample variances si2 (i = 1, ..., n), each respectively having νi degrees of freedom..." νi is the degrees of freedom for sample variance i. I've changed the font as the nu may have looked more like a v, depending on your browser font settings. --Qwfp (talk) 22:25, 23 March 2011 (UTC)[reply]

signs of a?

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Hello,

Does this mean that if I compute a difference

the effective degrees of freedom are zero? — Preceding unsigned comment added by 75.150.66.10 (talk) 19:23, 10 January 2012 (UTC)[reply]