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| From | Richard Goldstein <richgold@ix.netcom.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: graph results of bitest stratified with by(var) |
| Date | Thu, 23 Jan 2014 13:33:52 -0500 |
true ;-) On 1/23/14, 1:22 PM, Nick Cox wrote: > I see, but you can just calculate that from the -statsby- results. > > Nick > njcoxstata@gmail.com > > > On 23 January 2014 18:19, Richard Goldstein <richgold@ix.netcom.com> wrote: >> 1. Michael, if you look at -h levelsof- there is an example showing its >> use with -foreach- >> >> 2. Nick, I did not suggest -statsby- because Michael asked for something >> that is not in the return list (r(k)/r(N)) and I don't think that this >> is allowed with -statsby-, but maybe I'm wrong about that? >> >> Rich >> >> On 1/23/14, 1:07 PM, Nick Cox wrote: >>> -search foreach- does exactly what you ask, namely point to sources on >>> -foreach-. >>> >>> But -help statsby- does even better. >>> >>> Here's a dopey example. >>> >>> sysuse auto, clear >>> statsby N=r(N) k=r(k) p_l=r(p_l) p_u=r(p_u) , by(rep78): bitest >>> foreign=.2 >>> list >>> >>> Nick >>> njcoxstata@gmail.com >>> >>> On 23 January 2014 17:55, Michael McCulloch <mm@pinestreetfoundation.org> >>> >>>> Thank you Richard, that's exactly what I'm wanting to achieve. >>>> I understand now that -bysort- clears the scalars at each re-call. >>>> >>>> Can you point me to primers so I can learn how to wrap this into a -foreach- / -levelsof- loop? >>> >>> >>> On Jan 23, 2014, at 5:45 AM, Richard Goldstein wrote: >>>> >>>>> If I understand what you want correctly, you cannot do it with bysort >>>>> because each time you do the test the set of returned values (the >>>>> "r()"'s) will be replaced and the old ones lost >>>>> >>>>> you can do this within a -foreach- loop (you may need -levelsof- first) >>>>> in which you quietly do the -bitest- and then list your results for that >>>>> test and then do the next -bitest-, etc. >>>>> >>>>> here is an example of how to use the returned values: >>>>> >>>>> . sysuse auto >>>>> >>>>> . bitest foreign=.2 >>>>> >>>>> Variable | N Observed k Expected k Assumed p Observed p >>>>> -------------+------------------------------------------------------------ >>>>> foreign | 74 22 14.8 0.20000 0.29730 >>>>> >>>>> Pr(k >= 22) = 0.029904 (one-sided test) >>>>> Pr(k <= 22) = 0.984075 (one-sided test) >>>>> Pr(k <= 7 or k >= 22) = 0.041800 (two-sided test) >>>>> r; t=0.09 8:39:38 >>>>> >>>>> . di r(N) _skip(2) r(P_p) _skip(2) r(k)/r(N) _skip(2) r(p) >>>>> 74 .2 .2972973 .04179963 >>>>> >>>>> I have not put headers on the columns and have not done several other >>>>> things you might want (e.g., print format for results) but this should >>>>> give the basic idea, assuming I have correctly understood you >>> >>> On 1/23/14, 12:57 AM, Michael McCulloch wrote: >>> >>>>>> I am using bitest for a two-sided test on whether the mean of varB is different than 0.2, and testing on each level of varA: >>>>>> bysort varA: bitest varB=.2 >>>>>> >>>>>> varA has ~30 values. I wish to display these in a table (showing N, observed p, >>>>> expected p, and the two-sided p-value), without manual cut-and-paste, as >>>>> the test >>>>> will be used to monitor an ongoing training program. >>>>>> >>>>>> I note that the results of bitest are stored as: >>>>>> r(N) number N of trials >>>>>> r(P_p) assumed probability p of success >>>>>> r(k) observed number k of successes >>>>>> r(p_l) lower one-sided p-value >>>>>> r(p_u) upper one-sided p-value >>>>>> r(p) two-sided p-value >>>>>> >>>>>> However, I do not know how one uses these r(**) values. Can anyone suggest how one >>>>> would go about this? * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/