Chi square test for variance - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: Chi square test for variance (/thread-3427.html) |
Chi square test for variance - salvomic - 03-19-2015 11:53 AM Hi all, in Prime Inference App we have to tests for Chi2 (chi square): Goodness of Fit and 2-way-test... However I need to calc chi2 test having only s^2 and σ^2 (H_0: σ^2 = value, H_1: σ^2 ≠ value) (i.e. s^2 = 0.0153, σ^2 = 0.01, n=20) the test to confront with chi-square should be \[ X_{0}^{2}= \frac{(n-1)s^{2}}{σ_{0}^{2}} \] (for my data I should have X^2= 29.07 against chi-square(19,1-0.05)=30.14 and then reject H_0)... Can I do something already with Inference app? If not I hope to see also this test Chi2 for variance added in Inference App (chi2 test section) in a next upgrade of the firmware... :-) Thank you Salvo RE: Chi square test for variance - salvomic - 03-19-2015 03:09 PM my first propose is this one. chi2_variance() It calc X² test and compare with χ² (saying if H₀ is to be reject or not), then calc also p value and confidence interval... If you have other idea for improvement, please, suggest... Code:
Also, please, help: is it possible to display results graphically as in Inference in a normal program (not an App)? or help me to make ...an App I would indeed "mimic" the output of Inference... RE: Chi square test for variance - Wes Loewer - 03-19-2015 09:42 PM I agree, this would be very useful to have Hypothesis Testing and Confidence Intervals for standard deviation/variance for 1 and 2 sample cases. Interestingly, the TI84+ and Nspire calculators have the 2 sample F-Test for standard deviation, but none of the other standard deviation Intervals or Tests. That always struck me as being odd to leave certain ones out. -wes RE: Chi square test for variance - salvomic - 03-19-2015 10:03 PM (03-19-2015 09:42 PM)Wes Loewer Wrote: I agree, this would be very useful to have Hypothesis Testing and Confidence Intervals for standard deviation/variance for 1 and 2 sample cases. Indeed, Wes, you're right. RE: Chi square test for variance - salvomic - 03-19-2015 10:45 PM Another improvement for Inference could be Prediction Interval (not Confidence Interval) having mean x̅ (x_bar) and standard deviation of the sample, s... For now in Inference there is only Regression -> Prediction Interval, but this estimation need to have two lists: Xlist and Ylist... RE: Chi square test for variance - parisse - 03-20-2015 06:55 AM Xcas has the following commands for tests: - chisquaret (chi2 test) - normalt (normal) - studentt (Student) - kolmogorovt (K.-Smirnov) - wilcoxont (Wilcoxon) chisquaret takes 2 args: 2 samples or 1 sample and a distribution law (i.e. you can test adequation with more distributions than just the normal distribution). I don't think these commands are inside the Prime right now, might be an interesting addition... RE: Chi square test for variance - salvomic - 03-20-2015 10:20 AM (03-20-2015 06:55 AM)parisse Wrote: Xcas has the following commands for tests: thank you Parisse, I agree: why not include those (of some of them) tests in Prime? Especially in Inference app... Salvo RE: Chi square test for variance - Anders - 03-20-2015 04:50 PM Kolmogorov-Smirnov test and Student test are also important and are used a lot so as parisse suggested it would be a great addition to include the whole patrisse's list of test: - chisquaret (chi2 test) - normalt (normal) - studentt (Student) - kolmogorovt (K.-Smirnov) - wilcoxont (Wilcoxon) RE: Chi square test for variance - salvomic - 03-20-2015 10:26 PM (03-20-2015 04:50 PM)Anders Wrote: Kolmogorov-Smirnov test and Student test are also important and are used a lot so as parisse suggested it would be a great addition to include the whole patrisse's list of test: yes, Anders, I agree! Another thing I think it should be included in Inference: Test F for variances of two population: here there is my proposal... |