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| From | Nick Cox <njcoxstata@gmail.com> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | Re: st: graph results of bitest stratified with by(var) |
| Date | Thu, 23 Jan 2014 18:07:26 +0000 |
-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/