*My comments will appear after asterisks

* The first thing you Always want to do is open a log.

 

      name:  <unnamed>

       log:  C:\Users\Michael\Documents\newer web pages\soc_meth_proj3\fall_2014_logs\class1.log

  log type:  text

 opened on:  22 Sep 2014, 11:25:24

 

. describe

 

Contains data from C:\Users\Michael\Desktop\cps_mar_2000_new_unchanged.dta

  obs:       133,710                         

 vars:            55                          1 Feb 2009 13:36

 size:    14,574,390                         

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

              storage   display    value

variable name   type    format     label      variable label

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

year            int     %8.0g      yearlbl    Survey year

serial          long    %12.0g     seriallbl

                                              Household serial number

hhwt            float   %9.0g      hhwtlbl    Household weight

region          byte    %27.0g     regionlbl

                                              Region and division

statefip        byte    %57.0g     statefiplbl

                                              State (FIPS code)

metro           byte    %27.0g     metrolbl   Metropolitan central city status

metarea         int     %50.0g     metarealbl

                                              Metropolitan area

ownershp        byte    %21.0g     ownershplbl

                                              Ownership of dwelling

hhincome        long    %12.0g     hhincomelbl

                                              Total household income

pubhous         byte    %8.0g      pubhouslbl

                                              Living in public housing

foodstmp        byte    %8.0g      foodstmplbl

                                              Food stamp recipiency

pernum          byte    %8.0g      pernumlbl

                                              Person number in sample unit

perwt           float   %9.0g      perwtlbl   Person weight

momloc          byte    %8.0g      momloclbl

                                              Mother's location in the household

poploc          byte    %8.0g      poploclbl

                                              Father's location in the household

sploc           byte    %8.0g      sploclbl   Spouse's location in household

famsize         byte    %25.0g     famsizelbl

                                              Number of own family members in hh

nchild          byte    %18.0g     nchildlbl

                                              Number of own children in household

nchlt5          byte    %23.0g     nchlt5lbl

                                              Number of own children under age 5

                                                in hh

nsibs           byte    %18.0g     nsibslbl   Number of own siblings in household

relate          int     %34.0g     relatelbl

                                              Relationship to household head

age             byte    %19.0g     agelbl     Age

sex             byte    %8.0g      sexlbl     Sex

race            int     %37.0g     racelbl    Race

marst           byte    %23.0g     marstlbl   Marital status

popstat         byte    %14.0g     popstatlbl

                                              Adult civilian, armed forces, or

                                                child

bpl             long    %27.0g     bpllbl     Birthplace

yrimmig         int     %11.0g     yrimmiglbl

                                              Year of immigration

citizen         byte    %31.0g     citizenlbl

                                              Citizenship status

mbpl            long    %27.0g     mbpllbl    Mother's birthplace

fbpl            long    %27.0g     fbpllbl    Father's birthplace

hispan          int     %29.0g     hispanlbl

                                              Hispanic origin

educ99          byte    %38.0g     educ99lbl

                                              Educational attainment, 1990

educrec         byte    %23.0g     educreclbl

                                              Educational attainment recode

schlcoll        byte    %45.0g     schlcolllbl

                                              School or college attendance

empstat         byte    %30.0g     empstatlbl

                                              Employment status

occ1990         int     %78.0g     occ1990lbl

                                              Occupation, 1990 basis

wkswork1        byte    %8.0g      wkswork1lbl

                                              Weeks worked last year

hrswork         byte    %8.0g      hrsworklbl

                                              Hours worked last week

uhrswork        byte    %13.0g     uhrsworklbl

                                              Usual hours worked per week (last

                                                yr)

hourwage        int     %8.0g      hourwagelbl

                                              Hourly wage

union           byte    %33.0g     unionlbl   Union membership

inctot          long    %12.0g                Total personal income

incwage         long    %12.0g                Wage and salary income

incss           long    %12.0g                Social Security income

incwelfr        long    %12.0g                Welfare (public assistance) income

vetstat         byte    %10.0g     vetstatlbl

                                              Veteran status

vetlast         byte    %26.0g     vetlastlbl

                                              Veteran's most recent period of

                                                service

disabwrk        byte    %34.0g     disabwrklbl

                                              Work disability

health          byte    %9.0g      healthlbl

                                              Health status

inclugh         byte    %8.0g      inclughlbl

                                              Included in employer group health

                                                plan last year

himcaid         byte    %8.0g      himcaidlbl

                                              Covered by Medicaid last year

ftotval         double  %10.0g     ftotvallbl

                                              Total family income

perwt_rounded   float   %9.0g                 integer perwt, negative values

                                                recoded to 0

yrsed           float   %9.0g                 based on educrec

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

Sorted by:  sex

 

. tabulate race

 

                                 Race |      Freq.     Percent        Cum.

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

                                White |    113,475       84.87       84.87

                          Black/Negro |     13,626       10.19       95.06

         American Indian/Aleut/Eskimo |      1,894        1.42       96.47

            Asian or Pacific Islander |      4,715        3.53      100.00

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

                                Total |    133,710      100.00

 

*We noticed that there appear to me no missing values of race. This is because the missing values have been imputed.

 

. tabulate race, missing

 

                                 Race |      Freq.     Percent        Cum.

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

                                White |    113,475       84.87       84.87

                          Black/Negro |     13,626       10.19       95.06

         American Indian/Aleut/Eskimo |      1,894        1.42       96.47

            Asian or Pacific Islander |      4,715        3.53      100.00

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

                                Total |    133,710      100.00

 

. tabulate race [fweight= perwt_rounded]

 

                                 Race |      Freq.     Percent        Cum.

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

                                White |224,806,952       82.02       82.02

                          Black/Negro | 35,508,668       12.96       94.98

         American Indian/Aleut/Eskimo |  2,847,473        1.04       96.01

            Asian or Pacific Islander | 10,924,728        3.99      100.00

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

                                Total |274,087,821      100.00

 

* Note that there are 133K individuals in the CPS, but there are 274 Million individuals in the sample universe, which was the non-institutional population of the US in March, 2000. It is vital for you to keep in mind the difference between the sample population and the entire US population.

 

. summarize perwt_rounded

 

    Variable |       Obs        Mean    Std. Dev.       Min        Max

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

perwt_roun~d |    133710    2049.868    1083.244         93      14281

 

* The CPS is a roughly 1-in-2000 sample of the US.

 

. tabulate race, nolab

 

       Race |      Freq.     Percent        Cum.

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

        100 |    113,475       84.87       84.87

        200 |     13,626       10.19       95.06

        300 |      1,894        1.42       96.47

        650 |      4,715        3.53      100.00

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

      Total |    133,710      100.00

 

* race is actually coded numerically, and the numbers have labels attached to them for convenience and legibility. Keep in mind that if you want to tell Stata to look specifically at, let’s say the white population, you would asking for this numerically, i.e. if race==100 (and notice the double equal signs after the “if”).

 

. codebook race

 

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

race                                                                         Race

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

 

                  type:  numeric (int)

                 label:  racelbl

 

                 range:  [100,650]                    units:  10

         unique values:  4                        missing .:  0/133710

 

            tabulation:  Freq.   Numeric  Label

                        1.1e+05      100  White

                         13626       200  Black/Negro

                          1894       300  American Indian/Aleut/Eskimo

                          4715       650  Asian or Pacific Islander

 

. summarize age

 

    Variable |       Obs        Mean    Std. Dev.       Min        Max

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

         age |    133710    35.17964    22.21722          0         90

 

. tabulate age

 

                Age |      Freq.     Percent        Cum.

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

       Under 1 year |      1,713        1.28        1.28

                  1 |      1,932        1.44        2.73

                  2 |      1,950        1.46        4.18

                  3 |      1,939        1.45        5.63

                  4 |      1,965        1.47        7.10

                  5 |      1,998        1.49        8.60

                  6 |      2,059        1.54       10.14

                  7 |      2,176        1.63       11.77

                  8 |      2,163        1.62       13.38

                  9 |      2,243        1.68       15.06

                 10 |      2,202        1.65       16.71

                 11 |      2,083        1.56       18.27

                 12 |      2,035        1.52       19.79

                 13 |      2,047        1.53       21.32

                 14 |      1,979        1.48       22.80

                 15 |      2,046        1.53       24.33

                 16 |      1,965        1.47       25.80

                 17 |      1,998        1.49       27.29

                 18 |      1,847        1.38       28.67

                 19 |      1,826        1.37       30.04

                 20 |      1,722        1.29       31.33

                 21 |      1,687        1.26       32.59

                 22 |      1,638        1.23       33.81

                 23 |      1,622        1.21       35.03

                 24 |      1,662        1.24       36.27

                 25 |      1,666        1.25       37.52

                 26 |      1,640        1.23       38.74

                 27 |      1,726        1.29       40.03

                 28 |      1,801        1.35       41.38

                 29 |      1,995        1.49       42.87

                 30 |      1,907        1.43       44.30

                 31 |      1,991        1.49       45.79

                 32 |      1,890        1.41       47.20

                 33 |      1,898        1.42       48.62

                 34 |      2,024        1.51       50.13

                 35 |      2,134        1.60       51.73

                 36 |      2,123        1.59       53.32

                 37 |      2,099        1.57       54.89

                 38 |      2,064        1.54       56.43

                 39 |      2,228        1.67       58.10

                 40 |      2,190        1.64       59.74

                 41 |      2,115        1.58       61.32

                 42 |      2,137        1.60       62.92

                 43 |      2,091        1.56       64.48

                 44 |      2,114        1.58       66.06

                 45 |      2,118        1.58       67.64

                 46 |      1,939        1.45       69.10

                 47 |      1,957        1.46       70.56

                 48 |      1,827        1.37       71.93

                 49 |      1,767        1.32       73.25

                 50 |      1,865        1.39       74.64

                 51 |      1,802        1.35       75.99

                 52 |      1,825        1.36       77.35

                 53 |      1,695        1.27       78.62

                 54 |      1,301        0.97       79.59

                 55 |      1,323        0.99       80.58

                 56 |      1,324        0.99       81.57

                 57 |      1,304        0.98       82.55

                 58 |      1,128        0.84       83.39

                 59 |      1,129        0.84       84.24

                 60 |      1,154        0.86       85.10

                 61 |      1,051        0.79       85.89

                 62 |      1,073        0.80       86.69

                 63 |        938        0.70       87.39

                 64 |        952        0.71       88.10

                 65 |      1,014        0.76       88.86

                 66 |        869        0.65       89.51

                 67 |        926        0.69       90.20

                 68 |        908        0.68       90.88

                 69 |        904        0.68       91.56

                 70 |        913        0.68       92.24

                 71 |        885        0.66       92.90

                 72 |        770        0.58       93.48

                 73 |        797        0.60       94.08

                 74 |        814        0.61       94.68

                 75 |        796        0.60       95.28

                 76 |        704        0.53       95.81

                 77 |        646        0.48       96.29

                 78 |        687        0.51       96.80

                 79 |        602        0.45       97.25

                 80 |        514        0.38       97.64

                 81 |        476        0.36       97.99

                 82 |        425        0.32       98.31

                 83 |        427        0.32       98.63

                 84 |        325        0.24       98.87

                 85 |        306        0.23       99.10

                 86 |        248        0.19       99.29

                 87 |        209        0.16       99.44

                 88 |        172        0.13       99.57

                 89 |        155        0.12       99.69

90 (90+, 1988-2002) |        416        0.31      100.00

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

              Total |    133,710      100.00

 

* Age is topcoded to 90. You need to get used to looking up variables in the IPUMS CPS documentation to verify topcodes, sample universes and the like.

 

. summarize yrsed

 

    Variable |       Obs        Mean    Std. Dev.       Min        Max

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

       yrsed |    103226    12.77328    3.156011          0         17

 

* yrsed is a variable I created, from one of the educational categorical variables, educrec. Note that there are missing values of yrsed.

 

. tabulate age if yrsed==.

 

                Age |      Freq.     Percent        Cum.

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

       Under 1 year |      1,713        5.62        5.62

                  1 |      1,932        6.34       11.96

                  2 |      1,950        6.40       18.35

                  3 |      1,939        6.36       24.71

                  4 |      1,965        6.45       31.16

                  5 |      1,998        6.55       37.71

                  6 |      2,059        6.75       44.47

                  7 |      2,176        7.14       51.61

                  8 |      2,163        7.10       58.70

                  9 |      2,243        7.36       66.06

                 10 |      2,202        7.22       73.28

                 11 |      2,083        6.83       80.12

                 12 |      2,035        6.68       86.79

                 13 |      2,047        6.71       93.51

                 14 |      1,979        6.49      100.00

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

              Total |     30,484      100.00

 

* If you looked up the educational variable educrec in ipums, it should say that the sample universe is persons 15 years old and older. Everyone younger than 15 has missing values.

 

. sort sex

 

. by sex: summarize yrsed

 

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

-> sex = Male

 

    Variable |       Obs        Mean    Std. Dev.       Min        Max

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

       yrsed |     49353    12.79632    3.217925          0         17

 

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

-> sex = Female

 

    Variable |       Obs        Mean    Std. Dev.       Min        Max

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

       yrsed |     53873    12.75218    3.098084          0         17

 

* If we want to compare educational attainment, we probably ought to narrow the age range down.

 

 

. by sex: summarize yrsed if age>=25 & age<=34

 

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

-> sex = Male

 

    Variable |       Obs        Mean    Std. Dev.       Min        Max

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

       yrsed |      9027    13.31212    2.967666          0         17

 

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

-> sex = Female

 

    Variable |       Obs        Mean    Std. Dev.       Min        Max

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

       yrsed |      9511    13.55657    2.854472          0         17

 

* So, are young women in the CPS more educated than young men? This first question is not exactly the kind of statistical question we usually want to answer, because the educational attainments of all subjects in the CPS are known (leaving aside measurement error and imputation). The real question is whether the observed difference in the CPS is consistent with equal educational attainment between young men and young women in the whole US, and the answer to this question is *No*, for reasons we will be exploring more as the class goes forward.

 

 

. ttest yrsed if age>=25 & age<=34, 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

 

. log close

      name:  <unnamed>

       log:  C:\Users\Michael\Documents\newer web pages\soc_meth_proj3\fall_2014_

> logs\class1.log

  log type:  text

 closed on:  22 Sep 2014, 12:42:45

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