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From |
DEEPANKAR BASU <basu.15@osu.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: testing equality of means for survey data |

Date |
Fri, 23 Nov 2007 17:51:58 -0500 |

I am working with Stata 8. I am working with survey data (DHS data) and am studying fertility behaviour of families. I have complete birth history data for each family in the sample. I wish to test the following hypothesis: girls have, on average, larger number of sibling. This is how I proceed. I calculate the number of boys and girls in each family (*nboy* and *ngirl*); then, I do: quietly gen alive = nboy + ngirl quietly gen sibg = (alive - 1) if ngirl > 0 quietly gen sibb = (alive - 1) if nboy > 0 Thus, *sibg* is the number of sibling for girls and *sibb* is number of sibling for boys. Then, I do: gen smpwt = v005/1000000 svyset [pweight=smpwt], psu(v021) strata(v022) svymean sibg, subpop(ngirl) matrix t1 = e(b) matrix t2 = e(V) local t11 = e(N) svymean sibb, subpop(nboy) matrix t3 = e(b) matrix t4 = e(V) local t33 = e(N) gen sibeff = t1[1,1] - t3[1,1] local g1 = (t1[1,1] - t3[1,1])/sqrt((t2[1,1]/`t11')+(t4[1,1]/`t33')) Thus, *sibeff* gives me the difference in the average number of sibling for girls and boys and *g1* gives me the t-statistic for testing whether *sibeff* is significantly different from zero. I am getting the t-statistic as much larger than I expected; it is also much smaller if I do not correct for survey design and simply assume that I have a simple random sample. This is making me a little suspicious. My questions: 1) Am I making any mistake in my computation or reasoning? 2) Is there a better way to conduct this t-test? I looked at: http://www.ats.ucla.edu/STAT/stata/faq/svyttest.htm but did not find it useful. Thanks in advance. Deepankar * * 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/

**Follow-Ups**:**Re: st: testing equality of means for survey data***From:*"Austin Nichols" <austinnichols@gmail.com>

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