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From |
"moleps islon" <moleps2@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: error bars |

Date |
Wed, 18 Jun 2008 22:30:08 +0200 |

I found cibplot which does what I need in terms of bars with projecting error bars (cibplot x y, by(z)), however the graphs come out the same way as ciplot. In other words identical, despite tabing the different variables give completely different results. On Wed, Jun 18, 2008 at 10:21 PM, Maarten buis <maartenbuis@yahoo.co.uk> wrote: > Have a look at: > R. Newson (2003), "Confidence intervals and p-values for delivery to > the end user", The Stata Journal, 3(3), pp. 245--269. > http://www.stata-journal.com/article.html?article=st0043 > > I actually refered to that earlier (see below) > > -- Maarten > > > --- moleps islon <moleps2@gmail.com> wrote: > >> I' making a double error bar graph- e.g two different variables x and >> y with error bars categorised according to z. I've tried using ciplot >> x y, by(z) however I get a graph with two identical error bars >> (though >> different symbol, but identical values) for each instance of z. Any >> idea how to remedy this? If I need to make bars (a bar graph) for >> each category and then have the positive part of the error bar >> projecting from the top- how do I go about this? >> >> Regards >> >> >> On Mon, Jun 16, 2008 at 2:23 PM, Nick Cox <n.j.cox@durham.ac.uk> >> wrote: >> > Standard errors can come from lots of places, including the -ci- >> > command. >> > >> > Moleps seems to be implying that -ci- does the right calculation >> for his >> > or her purposes. >> > >> > (I note that Moleps has yearly results, but -ci- for separate years >> does >> > nothing about any time series structure in the data, for example >> about >> > taking serial correlation into account.) >> > >> > -ciplot- and -stripplot- from SSC both do -ci-type calculations and >> > graphing in one. >> > >> > Nick >> > n.j.cox@durham.ac.uk >> > >> > Maarten buis >> > >> > --- moleps islon <moleps2@gmail.com> wrote: >> >> I need to make a an error-bar graph categorised by year. I've >> tried >> >> using serrbar mean(x) etc, but I cant find a command for the >> standard >> >> error. Do I need to run a CI, generate a new variable from the ci >> >> result and feed that into serrbar? >> > >> > There are many ways of doing this. For instance you can use methods >> > discussed in (Buis 2007) (a convenient estimatation command would >> in >> > this case be -mean-), or you can remember that the standard error >> of >> > the mean is the standard deviation divided by the square root of >> the >> > number of observations, like in the example below: >> > >> > *-------------- begin example ----------------------- >> > sysuse nlsw88, clear >> > gen mis = missing(wage, age) >> > bys age: egen mwage = mean(wage) >> > bys age: egen sdwage = sd(wage) >> > bys age mis: gen se = sdwage/sqrt(_N) if mis == 0 >> > serrbar mwage se age, scale(1.96) >> > *-------------- end example ------------------------- >> > >> > Notice that a fixed scale is slightly problematic here as idealy >> this >> > scale should depend on the number of observations (a t-test), but >> 1.96 >> > should work fine in large samples. For a more flexible approach, >> where >> > you can take all this into account see: (Newson 2003) >> > >> > -- maarten >> > >> > M.L. Buis (2007), "Stata tip 54: Where did my p-values go?", The >> Stata >> > Journal, 7(4), pp.584--586. >> > http://home.fsw.vu.nl/m.buis/wp/pvalue.html >> > >> > R. Newson (2003), "Confidence intervals and p-values for delivery >> to >> > the end user", The Stata Journal, 3(3), pp. 245--269. >> > http://www.stata-journal.com/article.html?article=st0043 >> > >> > >> > * >> > * For searches and help try: >> > * http://www.stata.com/support/faqs/res/findit.html >> > * http://www.stata.com/support/statalist/faq >> > * http://www.ats.ucla.edu/stat/stata/ >> > >> * >> * For searches and help try: >> * http://www.stata.com/support/faqs/res/findit.html >> * http://www.stata.com/support/statalist/faq >> * http://www.ats.ucla.edu/stat/stata/ >> > > > ----------------------------------------- > Maarten L. Buis > Department of Social Research Methodology > Vrije Universiteit Amsterdam > Boelelaan 1081 > 1081 HV Amsterdam > The Netherlands > > visiting address: > Buitenveldertselaan 3 (Metropolitan), room Z434 > > +31 20 5986715 > > http://home.fsw.vu.nl/m.buis/ > ----------------------------------------- > > > __________________________________________________________ > Sent from Yahoo! Mail. > A Smarter Email http://uk.docs.yahoo.com/nowyoucan.html > * > * For searches and help try: > * http://www.stata.com/support/faqs/res/findit.html > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**Re: st: error bars***From:*"moleps islon" <moleps2@gmail.com>

**Re: st: error bars***From:*Maarten buis <maartenbuis@yahoo.co.uk>

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