Dear Authorized Sir / Madam, If you don't mind, I want to ask how can i calculate negative log of the E-Values in R. *For Example: * What is the negative log of the 4e-108? I would appreciate if you could advise me some methods. Thanks in advance. [[alternative HTML version deleted]]
On 26.02.2016 10:53, Sema Atasever wrote:> Dear Authorized Sir / Madam, > > If you don't mind, I want to ask how can i calculate negative log of the > E-Values in R. > > *For Example: * > What is the negative log of the 4e-108?what about log(4e-108) ? (although I wonder if this is numerical sensible at all...). Or do you want to know that 4e-108 == 4*10^(-108) ? Best, Uwe Ligges> > I would appreciate if you could advise me some methods. > > Thanks in advance. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >
Sema, E is just a computer way of saying 0. For the purpose of statistical analysis, if you can't compute a calculation with E values (i.e. 0), substitute all E values with a usable constant, say 50. I stumbled across a few websites lately that did this. Frank Romano Ph.D. *Academia.edu* https://sheffield.academia.edu/FrancescoRomano On Fri, Feb 26, 2016 at 10:53 AM, Sema Atasever <s.atasever at gmail.com> wrote:> Dear Authorized Sir / Madam, > > If you don't mind, I want to ask how can i calculate negative log of the > E-Values in R. > > *For Example: * > What is the negative log of the 4e-108? > > I would appreciate if you could advise me some methods. > > Thanks in advance. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >-- [[alternative HTML version deleted]]
I do hope that was a joke! -pd> On 26 Feb 2016, at 18:16 , Francesco Romano <francescobryanromano at gmail.com> wrote: > > Sema, E is just a computer way of saying 0. For the purpose of statistical > analysis, if you can't compute a calculation with E values (i.e. 0), > substitute all E values with a usable constant, say 50. I stumbled across a > few websites lately that did this. > > Frank Romano Ph.D. > > *Academia.edu* > https://sheffield.academia.edu/FrancescoRomano > > > On Fri, Feb 26, 2016 at 10:53 AM, Sema Atasever <s.atasever at gmail.com> > wrote: > >> Dear Authorized Sir / Madam, >> >> If you don't mind, I want to ask how can i calculate negative log of the >> E-Values in R. >> >> *For Example: * >> What is the negative log of the 4e-108? >> >> I would appreciate if you could advise me some methods. >> >> Thanks in advance. >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > > > -- > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.-- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
Actually E is not "just a computer way of saying 0". The E represents a power of 10, thus E-1 = 0.1 e-2=0.01; E therefore is not zero. Because computers generally can not perform exact calculations (for reasons including the fact that our number system is base 10 and a computer's is generally base 2) what might otherwise be a zero is often represented by a very small number such as the one you listed. 4E-108 would be 4x10^-108, a very small number indeed that is (for most but not all purposes) the same as zero. John> John David Sorkin M.D., Ph.D. > Professor of Medicine > Chief, Biostatistics and Informatics > University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine > Baltimore VA Medical Center > 10 North Greene Street > GRECC (BT/18/GR) > Baltimore, MD 21201-1524 > (Phone) 410-605-7119 > (Fax) 410-605-7913 (Please call phone number above prior to faxing)> On Feb 26, 2016, at 12:29 PM, Francesco Romano <francescobryanromano at gmail.com> wrote: > > Sema, E is just a computer way of saying 0. For the purpose of statistical > analysis, if you can't compute a calculation with E values (i.e. 0), > substitute all E values with a usable constant, say 50. I stumbled across a > few websites lately that did this. > > Frank Romano Ph.D. > > *Academia.edu* > https://sheffield.academia.edu/FrancescoRomano > > > On Fri, Feb 26, 2016 at 10:53 AM, Sema Atasever <s.atasever at gmail.com> > wrote: > >> Dear Authorized Sir / Madam, >> >> If you don't mind, I want to ask how can i calculate negative log of the >> E-Values in R. >> >> *For Example: * >> What is the negative log of the 4e-108? >> >> I would appreciate if you could advise me some methods. >> >> Thanks in advance. >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > > > -- > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.Confidentiality Statement: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message.