class 5 log

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name: <unnamed>

log: C:\Users\mexmi\Documents\newer web pages\soc_meth_proj3\Soc180B_spr2019_logs\class5_l

> og.log

log type: text

opened on: 16 Apr 2019, 14:45:04

. use "C:\Users\mexmi\Desktop\cps_mar_2000_new.dta", clear

. *class starts here

. tabulate occ1990 if occ1990==178| occ1990==95 | occ1990==125

Occupation, 1990 basis | Freq. Percent Cum.

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

Registered nurses | 966 68.37 68.37

Sociology instructors | 6 0.42 68.79

Lawyers | 441 31.21 100.00

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

Total | 1,413 100.00

. tabulate occ1990 if occ1990==178| occ1990==95 | occ1990==125, nolab

Occupation, |

1990 basis | Freq. Percent Cum.

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

95 | 966 68.37 68.37

125 | 6 0.42 68.79

178 | 441 31.21 100.00

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

Total | 1,413 100.00

* a reminder of which code stands for which occupation.

. table occ1990 if occ1990==178| occ1990==95 | occ1990==125, contents (freq mean incwage sd incwage)

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

Occupation, 1990 |

basis | Freq. mean(incwage) sd(incwage)

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

Registered nurses | 966 37536.85197 21839.96

Sociology instructors | 6 41508.33333 6963.219

Lawyers | 441 74044.32653 69032.96

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

* In order to get Excel to generate the t-tests, all you need are mean, sd, and n (i.e. unweighted frequency).

. graph box incwage if occ1990==178| occ1990==95 | occ1990==125, over (occ1990)

. graph hbox incwage if occ1990==178| occ1990==95 | occ1990==125, over (occ1990)

* Two versions of the box plot of incwage across our 3 occupations.

. table occ1990 if occ1990==178| occ1990==95 | occ1990==125, contents(freq p25 incwage p50 incwage p75 incwage)

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

Occupation, 1990 |

basis | Freq. p25(incwage) med(incwage) p75(incwage)

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

Registered nurses | 966 25000 37000 48000

Sociology instructors | 6 35000 41200 46000

Lawyers | 441 17000 61000 100960

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

* The top and bottom of the boxplot are 25^th percentile and 75^th percentile, and the middle is the median or 50^th percentile, whose values you can get directly from the table command above.

. summarize incwage if occ1990==178, detail

Wage and salary income

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

Percentiles Smallest

1% 0 0

5% 0 0

10% 0 0 Obs 441

25% 17000 0 Sum of Wgt. 441

50% 61000 Mean 74044.33

Largest Std. Dev. 69032.96

75% 100960 279376

90% 197387 279376 Variance 4.77e+09

95% 229339 279376 Skewness 1.132374

99% 257525 364302 Kurtosis 3.973892

* You can also use summarize, detail to give you the percentile distributions of each of the 3 occupations (lawyers above).

* The syntax for a ttest comparing incwage of nurses and sociologists:

. ttest incwage if occ1990==95|occ1990==125, by(occ1990)

Two-sample t test with equal variances

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

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

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

Sociolog | 6 41508.33 2842.722 6963.219 34200.88 48815.78

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

combined | 972 37561.37 698.6046 21780.33 36190.42 38932.32

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

diff | -3971.481 8923.041 -21482.17 13539.21

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

diff = mean(Register) - mean(Sociolog) t = -0.4451

Ho: diff = 0 degrees of freedom = 970

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

Pr(T < t) = 0.3282 Pr(|T| > |t|) = 0.6564 Pr(T > t) = 0.6718

* The same comparison, but with the unequal variance t-test.

. ttest incwage if occ1990==95|occ1990==125, by(occ1990)unequal

Two-sample t test with unequal variances

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

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

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

Sociolog | 6 41508.33 2842.722 6963.219 34200.88 48815.78

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

combined | 972 37561.37 698.6046 21780.33 36190.42 38932.32

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

diff | -3971.481 2928.283 -11252.58 3309.62

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

diff = mean(Register) - mean(Sociolog) t = -1.3562

Ho: diff = 0 Satterthwaite's degrees of freedom = 5.62958

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

Pr(T < t) = 0.1134 Pr(|T| > |t|) = 0.2269 Pr(T > t) = 0.8866

. log close

name: <unnamed>

log: C:\Users\mexmi\Documents\newer web pages\soc_meth_proj3\Soc180B_spr2019_logs\class5_l

> og.log

log type: text

closed on: 16 Apr 2019, 16:23:55

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