-------------------------------------------------------------

      name:  <unnamed>

       log:  C:\Documents and Settings\Michael Rosenfeld\My Documents\newer web pages\soc_meth_proj3\2010_logs\third_class_log.log

  log type:  text

 opened on:   2 Feb 2010, 14:55:44

. use "C:\Documents and Settings\Michael Rosenfeld\Desktop\cps_mar_2000_new.dta", clear

. table yrsed if age>24 & age<35, contents(freq mean yrsed sd yrsed)

rowvar variable(s) may not be used in contents()

r(111);

. table sex if age>24 & age<35, contents(freq mean yrsed sd yrsed)

-------------------------------------------------

      Sex |       Freq.  mean(yrsed)    sd(yrsed)

----------+--------------------------------------

     Male |       9,027     13.31212     2.967666

   Female |       9,511     13.55657     2.854472

-------------------------------------------------

. display 13.55657-13.31212

.24445

. *the difference between men and women's education in this age group is about one quarter of a year. Is that a big difference? Are we sure the women have more education?

. ttest yrsed if age>24 & age<35, by(sex)

Two-sample t test with equal variances

------------------------------------------------------------------------------

   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]

---------+--------------------------------------------------------------------

    Male |    9027    13.31212    .0312351    2.967666    13.25089    13.37335

  Female |    9511    13.55657    .0292693    2.854472    13.49919    13.61394

---------+--------------------------------------------------------------------

combined |   18538    13.43753    .0213921    2.912627     13.3956    13.47946

---------+--------------------------------------------------------------------

    diff |           -.2444469    .0427623               -.3282649   -.1606289

------------------------------------------------------------------------------

    diff = mean(Male) - mean(Female)                              t =  -5.7164

Ho: diff = 0                                     degrees of freedom =    18536

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0

 Pr(T < t) = 0.0000         Pr(|T| > |t|) = 0.0000          Pr(T > t) = 1.0000

* The t-statistic of -5.7, being much larger in absolute value than 2, demonstrates that this difference of .244 years between men and women in years of education is powerfully significant… See my Excel file where this problem is worked out by hand.

. exit, clear