Talk:Welch–Satterthwaite equation

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Underlying normal?[edit]

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[edit]

The following holds:

$\nu _{\chi '}{\frac {\chi '}{E[\chi ']}}$

follows approximately a chi-square distribution with $\nu _{\chi '}$ degrees of freedom.

k_i[edit]

The article talks about $k_{i}$ 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[edit]

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

s i 2 (i = 1, ..., n)

, each respectively having

ν i

degrees of freedom..."

ν i

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?[edit]

Hello,

Does this mean that if I compute a difference

$f(x_{1},x_{2})=x_{1}-x_{2}$

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

[1] ttps://math.stackexchange.com/questions/1746329/proof-and-precise-formulation-of-welch-satterthwaite-equation

[2] ttp://www.jstor.org/stable/2332510?seq=1#page_scan_tab_contents

[1]

[2]