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From | Nick Cox <n.j.cox@durham.ac.uk> |
To | "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu> |
Subject | st: RE: RE: RE: on counting and fractions in stata |
Date | Thu, 27 Oct 2011 13:18:52 +0100 |
You can naturally also go gen byte above = series > 3.1 su above, meanonly local mean = r(mean) local total = r(N) local count = r(sum) and any extra conditions can be put on the -summarize-. In each case, "series > 3.1" would in careful code be "series > 3.1 & series < ." Nick n.j.cox@durham.ac.uk -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox Sent: 27 October 2011 13:07 To: 'statalist@hsphsun2.harvard.edu' Subject: st: RE: RE: on counting and fractions in stata If you have other conditions, the pattern is count if series > 3.1 & <condition) local count = r(N) count if <condition> local total = r(N) local fraction = `count'/`total' Nick n.j.cox@durham.ac.uk Nick Cox . count if series > 3.1 . local count = r(N) . local total = _N . di `count' . di `total' . di `count'/`total' -count- is a much-overlooked command. People seemingly don't find it or think it too simple. See e.g. SJ-7-1 pr0029 . . . . . . . . . . . . . . . Speaking Stata: Making it count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox Q1/07 SJ 7(1):117--130 (no commands) discusses count used with a loop over observations or variables SJ-7-4 dm0033 . . . . . . Speaking Stata: Counting groups, especially panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox Q4/07 SJ 7(4):571--581 (no commands) discusses how to count panels through reduction commands or through tabulation commands and how to overcome problems that do not yield easily to these approaches Nick n.j.cox@durham.ac.uk rado645-bg@yahoo.de I face the following problem in Stata: I have a series of daily observations on a given variable and I also have one estimate of this variable that serves as a threshold. I would like to estimate how many times this threshold is exceeded by comparing the value of this estimate with the available data on daily observations. Is it possible to estimate fractions in Stata in this particular way? Below is a simple example: series estimate: 3.1 1.2 2.1 3.2 1.01 Given this data,I would like to get the following estimates (comments in brackets): count:1 (threshold is exceeded only once) fraction: 1/4=0.25 (one out of 4 cases) * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/