Hello everyone, Steve,
Just uploaded a first review on the CG7009 - Data analysis in the feedback folder. I agree with your suggestions and inserted them into the guide. A few notes: - It's possible to set different values for Alpha in other tools like F-test, Paired t-test, and Chi-test (the dialog do not give this option to the user). This is also true for the Hypothesized Mean Difference in the Paired t-test. In this case, I suggested in the chapter to expand your explanation to all of those tools. - I have updated the Figure, but this was my first time doing this, could you give a double check on this? Fell free to delete it and replace if the result was not OK. About the chapter, the instructions were very clear, and I managed to reproduce every step, just a few minor suggestions. The Calc Guide Status has been updated. Best regards, Felipe Viggiano Em sex., 4 de set. de 2020 às 05:15, Steve (GMail) < [email protected]> escreveu: > Thanks Felipe. > > I think we must describe what the software currently does in the Calc > Guide - enhancements can be requested via Bugzilla but they may or may not > happen depending on volunteer effort. > > In summary, it appears that we need to update the description in Chapter 9 > (and maybe the Help) as follows: > > 1. Include a statement that normally, if the sample size is not large > (n < 30), the Paired t-test tool may be more appropriate. > 2. After selecting the tool, the user should enter the variances of > the two datasets into the fields provided. In the example given the user > could enter the formula =VAR(A1:A13) into cell E5 and the formula > =VAR(B1:B13) into cell F5. The subsequent z and P values will be updated > automatically. > 3. The user can also update the required Alpha (cell E2) > and Hypothesised Mean Difference (cell E3) values. Again, the subsequent z > and P values will be updated automatically. > 4. State that the user should compare the selected Alpha level to the > appropriate calculated P value (depending whether a one-tailed or a > two-tailed test is required). If the calculated P value is smaller than the > Alpha level, then the user should reject the hypothesis (which, in the > example given, is that the means of the two data sets are the same). > 5. Update the figure accordingly. > > Does that make sense? > > Regards, > > Steve > > ------ Original Message ------ > From: "Felipe Viggiano" <[email protected]> > To: "Steve (GMail)" <[email protected]> > Cc: "Documentation Team" <[email protected]> > Sent: 04/09/2020 03:12:40 > Subject: Re: Re[2]: [libreoffice-documentation] Calc's Z-test tool > > Hello everyone, > > About the matter, I'm currently reviewing the > CG7009-DataAnalysis-SF-12Aug2020, and got to the Z-test tool part. > > After creating the results table, is possible to insert the variance in > their respective cells, but I was looking to the Z-test wiki page referred > in the chapter and it says this: > "*If the population variance is unknown (and therefore has to be > estimated from the sample itself) and the sample size is not large (n < > 30), the Student's t-test may be more appropriate.*" > > I just did a little research on google and found this website doing some > explanation about Z-Test: > https://www.solver.com/z-test-two-sample-means > When running the example in Calc and manually inserting the variances in > the cells of the Z-Test results, the output was identical to the example on > the website. > > So I'm guessing that LO Calc should be able to calculate the variance from > the given data, and this should be fixed in the software. > Or, maybe we can put a note to the user to insert the variances after > creating the table. > > Best regards, > Felipe Viggiano > > > > Em qua., 2 de set. de 2020 às 07:55, Steve (GMail) < > [email protected]> escreveu: > >> Thanks Ilmari and Mark, >> >> I'm happy to update the section in the 7.0 Calc Guide (which is >> currently in preparation) but I'm still confused. Why does the z-test >> tool think that the variance of the given data sets is zero? As you say >> Ilmari, that is not a number that the user currently enters. >> >> Regards, >> >> Steve >> >> ------ Original Message ------ >> From: "Ilmari Lauhakangas" <[email protected]> >> To: [email protected] >> Sent: 02/09/2020 11:40:06 >> Subject: Re: [libreoffice-documentation] Calc's Z-test tool >> >> >Thanks! That was my gut feeling. >> > >> >So the immediate action would be to change the screenshots in Help and >> Calc guide so the variance cells have non-zero values, also adding a note >> to the instructions. >> > >> >A further question is, should we consider adding fields for inputting >> variance values into the Z-test tool itself? Looking at Microsoft Office >> docs, Excel has these. This would become an enhancement request in Bugzilla. >> > >> >Ilmari >> > >> >Mark Morin kirjoitti 2.9.2020 klo 2.57: >> >>Variance can't be zero for analysis of variance tests (t test, F test, >> >>etc). Statistical testing assumes that you have variance otherwise you >> >>really wouldn't need a test. >> >> >> >>On 9/1/2020 4:48 PM, Ilmari Lauhakangas wrote: >> >>>I was looking at a bug report again: >> >>>https://bugs.documentfoundation.org/show_bug.cgi?id=132983 >> >>> >> >>>The reporter is scratching their head over the "division by zero" >> >>>result for z. >> >>> >> >>> From what I can see, the "Known variance" values can't both be zero, >> >>>if you want to avoid the #DIV/0! results. You have to give at least >> >>>one of them a positive non-zero value. >> >>> >> >>>Now, looking at Help: >> >>> >> https://help.libreoffice.org/7.1/en-US/text/scalc/01/statistics_test_z.html >> >>> >> >>> >> >>>and the Calc guide chapter CG7009-DataAnalysis-SF-12Aug2020, we see >> >>>this same "division by zero" result and the reader is left holding it. >> >>> >> >>>How to present this better in the docs? I have no experience on the >> >>>topic, but I hope we can find some statistician to shed light on this! >> >>> >> >>>Ilmari >> >>> >> >> >> > >> >-- To unsubscribe e-mail to: >> [email protected] >> >Problems? >> https://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/ >> >Posting guidelines + more: >> https://wiki.documentfoundation.org/Netiquette >> >List archive: https://listarchives.libreoffice.org/global/documentation/ >> >Privacy Policy: https://www.documentfoundation.org/privacy >> >> >> -- >> To unsubscribe e-mail to: >> [email protected] >> Problems? >> https://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/ >> Posting guidelines + more: https://wiki.documentfoundation.org/Netiquette >> List archive: https://listarchives.libreoffice.org/global/documentation/ >> Privacy Policy: https://www.documentfoundation.org/privacy >> > -- To unsubscribe e-mail to: [email protected] Problems? https://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/ Posting guidelines + more: https://wiki.documentfoundation.org/Netiquette List archive: https://listarchives.libreoffice.org/global/documentation/ Privacy Policy: https://www.documentfoundation.org/privacy
