Talk:Statistics/Chi-squared distribution: Difference between revisions

Content added Content deleted
m (Partially outdent last comment.)
Line 101: Line 101:
: That said, there's a small j wiki [[j:Essays/Chi_Squared_CDF|entry]] on this subject which claims to include an example which matches "calculated results against values from the [[WikiPedia:Handbook_of_Mathematical_Functions|Handbook of Mathematical Functions]] by Abramowitz and Stegun, Table 26.8." --[[User:Rdm|Rdm]] ([[User talk:Rdm|talk]]) 09:59, 2 October 2022 (UTC)
: That said, there's a small j wiki [[j:Essays/Chi_Squared_CDF|entry]] on this subject which claims to include an example which matches "calculated results against values from the [[WikiPedia:Handbook_of_Mathematical_Functions|Handbook of Mathematical Functions]] by Abramowitz and Stegun, Table 26.8." --[[User:Rdm|Rdm]] ([[User talk:Rdm|talk]]) 09:59, 2 October 2022 (UTC)


:: Well, the Wikipedia formula looks correct to me. If we substitute k = 2 in their formula for the pdf (which agrees with the task description so there's no notational difference here) we get (since gamma(1) = 1):
Well, the Wikipedia formula looks correct to me. If we substitute k = 2 in their formula for the pdf (which agrees with the task description so there's no notational difference here) we get (since gamma(1) = 1):


:: f(x; k) = exp(-x/2) / 2
:: f(x; k) = exp(-x/2) / 2


:: and if we integrate that we get:
and if we integrate that we get:


:: F(x; k) = 1 - exp(-x/2)
:: F(x; k) = 1 - exp(-x/2)


--[[User:PureFox|PureFox]] ([[User talk:PureFox|talk]]) 10:48, 2 October 2022 (UTC)
[[User:PureFox|PureFox]] ([[User talk:PureFox|talk]]) 10:48, 2 October 2022 (UTC)