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Screensize: 640 x 480 800 x 600 1024 x 768 1280 x 1024 UserName: Password: Anti-Spam Code: Format Mode: Basic  Help  Prompt  Format: Font Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Size 1 2 3 4 5 6   Color Black Red Yellow Pink Green Orange Purple Blue Beige Brown Teal Navy Maroon LimeGreen Message: * HTML is OFF * Forum Code is ON Smilies [quote][i]Originally posted by holyone2[/i] [br]Origin Ver. and Service Release (Select Help-->About Origin): 9.1.0 (64-bit) Operating System: Win 10 Pro I performed an non-linear fit to an expression of the form: y=exp(ln(10)k/x)-1 Where: k is parameter (VT) y (sens_perc_unbounded) x (SS) Image of result here: [url]https://www.dropbox.com/s/kbulky02h1hy8i4/Untitled.png?dl=0[/url] Despite apparently a good fit the ANOVA gives a Prob>F value of 1, which I believe means far from statistically significant. As I understand it based on this: [url]http://www.originlab.com/doc/Origin-Help/NLFit-Theory#ANOVA_Table[/url], the value is the p-value, so as its not small I cannot reject the null hypothesis that y=constant (where constant is the mean of the y values, I read on a different website). Clearly y=constant would be a much poorer fit to this function, so I don't understand the result. - I'd also be interested if anyone knows what the null hypothesis is for the test found at: "fitting> non-linear curve fitting> advanced > quantities to computer >t-value" ? I'd be grateful for any help. [/quote]   Check here to include your profile signature. Check here to subscribe to this topic.