***************************************************************
* *
* Two Sample T-test and Confidence Interval *
* for the Mean BMI Difference Between Males and Females *
* *
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insheet using http://hedwig.mgh.harvard.edu/biostatistics/sites/default/files/public/education/tmp_sample_data.csv
ttest bmi, by(gender)
********************************** ANNOTATED RESULTS **********************************
Two-sample t test with equal variances
------------------------------------------------------------------------------
Group | Obs Mean Std. Err. Std. Dev. [95% Conf. Interval]
---------+--------------------------------------------------------------------
0 | 16 25.9375 .7783462 3.113385 24.27849 27.59651
1 | 44 26.03182 .6033362 4.002079 24.81507 27.24856
---------+--------------------------------------------------------------------
combined | 60 26.00667 .4854427 3.760223 25.0353 26.97804
---------+--------------------------------------------------------------------
diff | -.0943184 1.107102 -2.310424 2.121788
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diff = mean(0) - mean(1) t = -0.0852
Ho: diff = 0 degrees of freedom = 58
Ha: diff < 0 Ha: diff != 0 Ha: diff > 0
Pr(T < t) = 0.4662 Pr(|T| > |t|) = 0.9324 Pr(T > t) = 0.5338