Chapter 01 - The Nature of Econometrics and Economic Data#
import stata_setup
stata_setup.config("C:/Program Files/Stata18/", "se", splash=False)
Problem C1#
i Average, minimum and maximum years of education
%%stata
use wage1.dta, clear
sum educ
. use wage1.dta, clear
. sum educ
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
educ | 526 12.56274 2.769022 0 18
.
ii Average hourly wage
%%stata
mean wage
Mean estimation Number of obs = 526
--------------------------------------------------------------
| Mean Std. err. [95% conf. interval]
-------------+------------------------------------------------
wage |
5.896103 .1610262 5.579768 6.212437
--------------------------------------------------------------
iii. CPI_1976 = 56.9 CPI_2010 = 218.056. Source: usinflationcalculator.com accessed 07112018
v. How many women? men?
%%stata
d female
count if female==1
count if female==0
. d female
Variable Storage Display Value
name type format label Variable label
-------------------------------------------------------------------------------
female byte %8.0g =1 if female
. count if female==1
252
. count if female==0
274
.
Problem C2#
i. Women in the sample? how many women smoking during pregnancy?
%%stata
use bwght.dta, clear
d cigs
count if cigs>0
display _N
. use bwght.dta, clear
. d cigs
Variable Storage Display Value
name type format label Variable label
-------------------------------------------------------------------------------
cigs byte %8.0g cigs smked per day while preg
. count if cigs>0
212
. display _N
1388
.
ii. Average cigs
%%stata
mean cigs
Mean estimation Number of obs = 1,388
--------------------------------------------------------------
| Mean Std. err. [95% conf. interval]
-------------+------------------------------------------------
cigs | 2.087176 .1603153 1.772689 2.401663
--------------------------------------------------------------
iii. Average cigs among smoking women
%%stata
sum cigs if cigs>0
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
cigs | 212 13.66509 8.690907 1 50
iv. Average fatheduc
%%stata
sum fatheduc
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
fatheduc | 1,192 13.18624 2.745985 1 18
v. Average and Standard deviation of Family income
%%stata
sum faminc
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
faminc | 1,388 29.02666 18.73928 .5 65
Problem C3#
i. max & min of math4
vi. Average and SD of exppp sum exppp display r(mean) ” and ” r(sd) vii. %age comaparison display 100[(6000-5500)/5500] display 100[ln(6000)-ln(5500)]
%%stata
u meap01, clear
sum math4
. u meap01, clear
(Written by R. )
. sum math4
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
math4 | 1,823 71.909 19.95409 0 100
.
ii. How many schools (%) have a perfect pass rate of math4?
%%stata
count if math4==100
display _N
. count if math4==100
38
. display _N
1823
.
iii. exactly 50%?
%%stata
count if math4==50
17
iv. Average pass rate for math4 & read4
%%stata
mean math4 read4
Mean estimation Number of obs = 1,823
--------------------------------------------------------------
| Mean Std. err. [95% conf. interval]
-------------+------------------------------------------------
math4 | 71.909 .4673461 70.99241 72.82559
read4 | 60.06188 .44845 59.18235 60.94141
--------------------------------------------------------------
v. Correlation between math4 & read4
%%stata
corr math4 read4
(obs=1,823)
| math4 read4
-------------+------------------
math4 | 1.0000
read4 | 0.8427 1.0000
Problem C4#
i. Fraction of men receiving job training
%%stata
u jtrain2.dta, clear
d train
mean train
. u jtrain2.dta, clear
. d train
Variable Storage Display Value
name type format label Variable label
-------------------------------------------------------------------------------
train byte %9.0g =1 if assigned to job training
. mean train
Mean estimation Number of obs = 445
--------------------------------------------------------------
| Mean Std. err. [95% conf. interval]
-------------+------------------------------------------------
train | .4157303 .0233895 .3697624 .4616982
--------------------------------------------------------------
.
ii. Average re78 for men receiving and not receiving job training
%%stata
sum re78 if train==1
sum re78 if train==0
. sum re78 if train==1
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
re78 | 185 6.349145 7.867405 0 60.3079
. sum re78 if train==0
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
re78 | 260 4.554802 5.483837 0 39.4835
.
iii.
%%stata
d unem78
count if train==1 & unem78==1
count if train==1
display 45/85
count if train==0 & unem78==1
count if train==0
display 92/260
.
. d unem78
Variable Storage Display Value
name type format label Variable label
-------------------------------------------------------------------------------
unem78 byte %9.0g =1 if unem. all of 1978
. count if train==1 & unem78==1
45
. count if train==1
185
. display 45/85
.52941176
. count if train==0 & unem78==1
92
. count if train==0
260
. display 92/260
.35384615
.
iv. was the job training program effective?
Problem C5#
i. Max, min & mean of children
%%stata
u fertil2, clear
sum children
. u fertil2, clear
. sum children
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
children | 4,361 2.267828 2.222032 0 13
.
ii. Percentage of Women who have electricity
%%stata
count if electric==1
display 100*r(N)/_N "%"
. count if electric==1
611
. display 100*r(N)/_N "%"
14.010548%
.
iii. Average of children for women who have and have not electricity
%%stata
mean children if electric==1
mean children if electric==0
. mean children if electric==1
Mean estimation Number of obs = 611
--------------------------------------------------------------
| Mean Std. err. [95% conf. interval]
-------------+------------------------------------------------
children | 1.898527 .0729547 1.755254 2.0418
--------------------------------------------------------------
. mean children if electric==0
Mean estimation Number of obs = 3,747
--------------------------------------------------------------
| Mean Std. err. [95% conf. interval]
-------------+------------------------------------------------
children | 2.327729 .0372054 2.254784 2.400674
--------------------------------------------------------------
.
iv. can you infer that having electricity “causes” women to have fewer children?
Problem C6#
i. How many countries in total? how many with zero murders
%%stata
u countymurders, clear
keep if year==1996
display _N
count if murders==0
. u countymurders, clear
(Written by R. )
. keep if year==1996
(35,152 observations deleted)
. display _N
2197
. count if murders==0
1,051
.
ii. Maximum murders? Maximum executions? Average executions?
%%stata
sum murders execs
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
murders | 2,197 6.390077 39.76102 0 1403
execs | 2,197 .0159308 .14226 0 3
iii. Correlation rate between murders & execs
%%stata
corr murders execs
(obs=2,197)
| murders execs
-------------+------------------
murders | 1.0000
execs | 0.2095 1.0000
iv. Do you think that more executions cause more murders to occur?
Problem C7#
i. %age of men abusing alcohol? employment rate?
%%stata
u alcohol, clear
sum abuse
display 100*r(mean) "%"
sum unem
display 100-r(mean) "%"
. u alcohol, clear
(Written by R. )
. sum abuse
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
abuse | 9,822 .0991651 .2988988 0 1
. display 100*r(mean) "%"
9.9165139%
. sum unem
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
unemrate | 9,822 5.569212 1.505064 2.8 10.9
. display 100-r(mean) "%"
94.430788%
.
ii. Emplyment rate for alcohol abusers?
%%stata
sum unem if abuse==1
display 100-r(mean) "%"
. sum unem if abuse==1
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
unemrate | 974 5.515708 1.507293 2.8 10.9
. display 100-r(mean) "%"
94.484292%
.
iii. Emplyment rate for non-abusers
%%stata
sum unem if abuse==0
display 100-r(mean) "%"
. sum unem if abuse==0
Variable | Obs Mean Std. dev. Min Max
-------------+---------------------------------------------------------
unemrate | 8,848 5.575102 1.504787 2.8 10.9
. display 100-r(mean) "%"
94.424898%
.
iv. Discuss the difference in answers to parts(ii) and (iii).