| Summary: | Data Analysis T test error in formula for standard error of the difference of sample means | ||
|---|---|---|---|
| Product: | LibreOffice | Reporter: | ejbarth |
| Component: | Calc | Assignee: | Not Assigned <libreoffice-bugs> |
| Status: | RESOLVED NOTABUG | ||
| Severity: | normal | CC: | ilmari.lauhakangas, jbfaure, miguelangelrv, raal, rb.henschel, xiscofauli |
| Priority: | medium | ||
| Version: | unspecified | ||
| Hardware: | All | ||
| OS: | All | ||
| Whiteboard: | |||
| Crash report or crash signature: | Regression By: | ||
| Bug Depends on: | |||
| Bug Blocks: | 108827 | ||
| Attachments: | The attached shows bug in Data Statistics T test | ||
raal: any idea about this? (In reply to Buovjaga from comment #1) > raal: any idea about this? @Raal, do you have any idea about it? M.a.riosv, do you have any idea about this? No, sorry. @ ejbarth@gmail.com : Please could you explain what values in your test file should be compared to see if it works as expected or if there is a problem. In your file I see one red cell and 2 yellow cells. Could you provide a reference showing that your own computations are correct. Did you try with current version of LibreOffice ? Which version did you use ? With LO 6.0.2 I do not see the ratio of 2 between values computed by your test file. Please provide more detailed explanations. Set status to NEEDINFO, please set it back to UNCONFIRMED once requested informations are provided. Best regards. JBF Dear Bug Submitter, This bug has been in NEEDINFO status with no change for at least 6 months. Please provide the requested information as soon as possible and mark the bug as UNCONFIRMED. Due to regular bug tracker maintenance, if the bug is still in NEEDINFO status with no change in 30 days the QA team will close the bug as INSUFFICIENTDATA due to lack of needed information. For more information about our NEEDINFO policy please read the wiki located here: https://wiki.documentfoundation.org/QA/Bugzilla/Fields/Status/NEEDINFO If you have already provided the requested information, please mark the bug as UNCONFIRMED so that the QA team knows that the bug is ready to be confirmed. Thank you for helping us make LibreOffice even better for everyone! Warm Regards, QA Team MassPing-NeedInfo-Ping-20181009 Dear Bug Submitter, Please read this message in its entirety before proceeding. Your bug report is being closed as INSUFFICIENTDATA due to inactivity and a lack of information which is needed in order to accurately reproduce and confirm the problem. We encourage you to retest your bug against the latest release. If the issue is still present in the latest stable release, we need the following information (please ignore any that you've already provided): a) Provide details of your system including your operating system and the latest version of LibreOffice that you have confirmed the bug to be present b) Provide easy to reproduce steps – the simpler the better c) Provide any test case(s) which will help us confirm the problem d) Provide screenshots of the problem if you think it might help e) Read all comments and provide any requested information Once all of this is done, please set the bug back to UNCONFIRMED and we will attempt to reproduce the issue. Please do not: a) respond via email b) update the version field in the bug or any of the other details on the top section of our bug tracker Warm Regards, QA Team MassPing-NeedInfo-20181105 I think, that the attached document compares the wrong functions. The wizard calculates a "Paired t-test". Therefore the variables need to have the same count of samples and you need to compare it with T.Test with type=1. If I call the wizard with 170 values from both F and M and use the T.Test function with type=1, I get the same result. |
Created attachment 129912 [details] The attached shows bug in Data Statistics T test in Data Statistics T-test: t statistic is currently computed using a formula like this: =($Sheet3.$E$21 - $Sheet3.$E$15) / ($Sheet3.$E$22 / ( $Sheet3.$E$23 + 1)) ^ 0.5 This leads to p values that are approximately half the correct values. The t statistic should use a formula like this: =(F17-E17)/SQRT(E18/E19+F18/F19) the terms in the square root are s1^2/n1 + s2^2/n2 This correction leads to results which are comparable to the cell function t.test