# 2.3 Sample selectivity bias  (Page 4/6)

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We are interested in only a subset of these data. Table 2 reports the definitions of variables that are relevant for our analysis. We can get further insight into the data set using the summarize command. Table 3 reports the summary statistics for the data set.

 Variable name Definition country County of residence (categorical variable equal to 0, 1, ..., 9) age Age of the woman education Number of years of education of the woman married Dummy variable equal to 1 if the woman is married and 0 otherwise children Number of children that the woman has in their household wage Hourly wage rate of the woman lw Natural logarithm of hourly wage rate work Dummy variable equal to 1 if the individual is in the workforce and 0 otherwise
 Variable Obs Mean Std. Dev Min Max Age 2000 36.208 8.28656 20 59 education 2000 13.084 3.045912 10 20 married 2000 .6705 .4701492 0 1 children 2000 1.6445 1.398963 0 5 wage 1343 23.69217 6.305374 5.88497 45.80979 lw 1343 3.126703 .2865111 1.772402 3.824498 work 2000 .6715 .4697852 0 1

We are interested in modeling two things: (1) the decision of the woman to enter the labor force and (2) determinants of the female wage rate. It might be reasonable to assume that the decision to enter the labor force by a woman is a function of age, marital status, the number of children, and her level of education. Also, the wage rate a woman earns should be a function of her age and education.

## The decision to enter the labor force

We can use a probit regression to model the decision of a woman to enter the labor force. The results of this estimation are reported in Table 4. However, we can use the predict command to produce some results that we can use to be sure that we understand what the regression results mean. In particular, type in the following two commands:

.predict zbhat, xb

.predict phat, p

These two commands will predict (1) the linear prediction (zbhat) and (2) the predicted probability that the woman will be in the workforce (phat). Table 5 reports the values of these two variables for observations 1 through 10.

 . probit work age education married children Iteration 0: log likelihood = -1266.2225 Iteration 4: log likelihood = -1027.0616 Probit estimates Number of obs = 2000 LR chi2(4) = 478.32 Prob>chi2 = 0.0000 Log likelihood = -1027.0616 Pseudo R2 = 0.1889 work Coef. Std. Err. z P>z [95% Conf. Interval] age .0347211 .0042293 8.21 0.000 .0264318 .0430105 education .0583645 .0109742 5.32 0.000 .0368555 .0798735 married .4308575 .074208 5.81 0.000 .2854125 .5763025 children .4473249 .0287417 15.56 0.000 .3909922 .5036576 _cons -2.467365 .1925635 -12.81 0.000 -2.844782 -2.089948
 Observation zbhat phat 1 -0.68900 0.24541 2 -0.20290 0.41961 3 -0.48067 0.31538 4 -0.16818 0.43322 5 0.34859 0.63630 6 0.58758 0.72159 7 0.97357 0.83486 8 0.45978 0.67716 9 0.01799 0.50718 10 0.32628 0.62790

where we get a research paper on Nano chemistry....?
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
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