improved shapes in cross section and longitudinal profile

... monitoring HSV loads in clinical samples [21,23] Some of the challenges in ascertaining these issues are related to intermittent nature and wide variability in the frequency and amount of HSV shedding ... presence and quantity of CVL HSV DNA were explored in relation to observed cross- sectional and longitudinal clinical data Page of women across six sites in the US (Los Angeles, CA; Washington, ... by quantitative TaqMan PCR: correlating single detection and quantity of HSV-2 DNA in cervicovaginal lavage fluids with cross- sectional and longitudinal clinical data Virology Journal 2010 7:328...

Ngày tải lên: 12/08/2014, 02:20

... as 11 points (Table 5), correctly classifying 75% of the 'improved' and 77% of the 'unchanged' participants Discussion In this cross- sectional and longitudinal study of patients with dizziness, ... proposed in test-retest reliability studies [27], while in our study of test-retest reliability, only 27 participants were included SDDind estimated in sample were in line with the initial findings in ... higher in sample Duration of dizziness was longer in sample than in sample All the participants in sample 2, and the majority of participants in sample had dizziness of vestibular origin, mainly...

Ngày tải lên: 18/06/2014, 19:20

... by section number and, sometimes, subsection number Therefore, Section 6.3 refers to Section in Chapter 6, and Section 13.8.3 refers to Subsection of Section in Chapter 13 By always including ... Models Introduction The Linear Probability Model for Binary Response Index Models for Binary Response: Probit and Logit Maximum Likelihood Estimation of Binary Response Index Models Testing in Binary ... Part II begins by applying these tools to the analysis of singleequation linear models using cross section data In principle, much of this material should be review for students having taken a...

Ngày tải lên: 06/07/2014, 08:20

... ahead of time as being random It is safe to say that no one ever went astray by assuming random sampling in place of independent sampling with fixed explanatory variables Random sampling does exclude ... reserved for indexing cross section units, such as individual, firm, city, and so on Letters such as j, g, and h will be used to index variables, parameters, and equations Before ending this example, ... not random samples from the population of interest In Chapter 17 we discuss such problems at length, including sample selection and stratified sampling As we will see, even in cases of nonrandom...

Ngày tải lên: 06/07/2014, 08:20

... to obtain estimable equations involving the parameters of an underlying conditional expectation of interest Problems 2.2 and 2.3 show how the linear projection can have an interesting interpretation ... conditional expectation linear in parameters can be written as a conditional expectation linear in parameters and linear in some conditioning variables If we write equation (2.29) in error form as y ... smaller information set always dominates.’’ Here, x represents less information than w, since knowing w implies knowing x, but not vice versa We will use equations (2.19) and (2.20) almost routinely...

Ngày tải lên: 06/07/2014, 08:20

... analysis 3.3 Convergence in Distribution definition 3.6: A sequence of random variables fxN : N ¼ 1; 2; g converges in distribution to the continuous random variable x if and only if FN ðxÞ ! F ... given in Section 3.4), which says that xN ðsN À NpÞ=½Npð1 À pފ 1=2 has a limiting standard normal distribution, where sN has the binomial ðN; pÞ distribution definition 3.7: A sequence of K  random ... or F distributed and then choosing a critical value based on this distribution Thus, testing using asymptotic methods is practically the same as testing using the classical linear model A test...

Ngày tải lên: 06/07/2014, 08:20

... way to handle the nonobservability of q is to put it into the error term In doing so, nothing is lost by assuming EðqÞ ¼ because an intercept is included in equation (4.19) Putting q into the ... will see in Sections 4.3 and 4.4, often an estimable equation is obtained only after manipulating an underlying structural equation An important point to remember is that, once the linear (in parameters) ... linear in the parameters under random sampling, identi- The Single-Equation Linear Model and OLS Estimation 53 fication of b simply means that b can be written in terms of population moments in...

Ngày tải lên: 06/07/2014, 08:20

... Convincing instruments sometimes arise in the context of program evaluation, where individuals are randomly selected to be eligible for the program Examples include job training programs and ... be drafted Again, unless we can include measures of job training in the earnings equation, condition (5.3) may be violated (This reasoning assumes that we are interested in estimating the pure ... estimating the pure e¤ect of serving in Vietnam, as opposed to including indirect e¤ects such as reduced job training.) Instrumental Variables Estimation of Single-Equation Linear Models 89 Hoxby (1994)...

Ngày tải lên: 06/07/2014, 08:20

... putting in strata dummies and applying 2SLS does not work: by definition, the instruments only vary across strata—not within strata and so b in equation (6.34) would be unidentified In the job training ... fatheduc, and huseduc and obtain the ^ ^ residuals, v Then we simply include v along with unity, exper, exper , and educ in ^ an OLS regression and obtain the t statistic on v Using the data in MROZ.RAW ... clear that the incinerator would be operating soon a Using the 1981 cross section, estimate a bivariate, constant elasticity model relating housing price to distance from the incinerator Is this...

Ngày tải lên: 06/07/2014, 08:20

... reason to use a SUR software routine in obtaining the estimates: we may be interested in testing joint hypotheses involving parameters ^ in di¤erent equations In order to so we need to estimate ... probability approaching one as N ! y We can write b à using full matrix notation as b à ¼ ½X IN n WÀ1 ÞXŠÀ1 Á ½X IN n WÀ1 ÞYŠ, where X and Y are the data matrices defined in Section 7.3.2 and IN is the ... SGLS.1 comes in We can argue this point informally because WÀ1 Xi is a linear combination of Xi , and since each element of Xi is uncorrelated with each element of ui , any linear combination of...

Ngày tải lên: 06/07/2014, 08:20

... enrolled in school and HeadStarti is a binary indicator equal to one if child i participated in Head Start at an early age The vector zi1 contains other observed factors, such as income, education, and ... by estimating b and b jointly, 186 Chapter that is, by using a system procedure The e‰ciency gains are analogous to the gains that can be realized by using feasible GLS rather than OLS in a SUR ... Zi and Zi0 Xi for each i.) In other words, we estimate the first equation by 2SLS using instruments zi1 , the second equation by 2SLS using instruments zi2 , and so on When we stack these into...

Ngày tải lên: 06/07/2014, 08:20

... is inf ¼ d10 þ g12 open þ d11 logð pcincÞ þ u1 open ¼ d20 þ g21 inf þ d21 logð pcincÞ þ d22 logðlandÞ þ u2 Assuming that pcinc (per capita income) and land (land area) are exogenous, under what ... exogenous variables, and probably contains unity We maintain assumption (9.2) throughout this section and also assume that Eðz zÞ is nonsingular The notation here di¤ers from that in Section 9.2.1 Here, ... have covered apply, including the tests of overidentifying restrictions in Chapters and 8, and the single-equation tests for endogeneity in Chapter 222 Chapter When estimating a simultaneous...

Ngày tải lên: 06/07/2014, 08:20

... including any binary indicators indicating participation in the program The estimates should be interpreted in the orginal equation because it allows us to think of comparing di¤erent units in the ... control and treatment groups available at two points in time In applying first di¤erencing, we should di¤erence all variables appearing in the structural equation to obtain the estimating equation, including ... that for a random e¤ects analysis.) Example 10.5 (FE Estimation of the E¤ects of Job Training Grants): Using the data in JTRAIN1.RAW, we estimate the e¤ect of job training grants using the fixed...

Ngày tải lên: 06/07/2014, 08:20

... where sibling (in some cases twin) di¤erences have been used in economics include Geronimus and Korenman (1992), Ashenfelter and Krueger (1994), Bronars and Grogger (1994), and Ashenfelter and Rouse ... cluster-level covariates, individual-level covariates, and possibly interactions of these in an initial model, and then to make inference in pooled OLS robust to arbitrary heteroskedasticity and cluster correlation ... because of an unexpected change in the tax laws [Such changes occurred in California in 1978 (Proposition 13) and in Michigan in 1994 (Proposal A).] Using lagged spending changes as IVs is probably...

Ngày tải lên: 06/07/2014, 08:20

... estimator (12.44) of Ao is useful in cases where E½Hðw; yo Þ j xŠ can be obtained in closed form or is easily approximated In some leading cases, including NLS and certain maximum likelihood problems, ... available in Gallant (1987), Gallant and White (1988), and White (1994) See Andrews (1989) for innovative suggestions for using local power analysis in applied work 12.7 Optimization Methods In this section ... covers cross section models with many equations, and it also covers panel data settings with small time series dimension The extension to independently pooled cross sections is almost immediate In...

Ngày tải lên: 06/07/2014, 08:20

... LM statistic for nonlinear regression in Section 12.6.2 We will use it in several applications in Part IV, including binary response models and Poisson regression models In these examples, the ... contain anything, including conditioning variables z t , lags of these, and lagged values of y The vector y consists of all parameters appearing in ft for any t; some or all of these may appear in ... main- 404 Chapter 13 tained, often implicitly by taking z t to be nonrandom In Chapter we saw that strict exogeneity played no role in getting consistent, asymptotically normal estimators in linear...

Ngày tải lên: 06/07/2014, 08:20

... are needed in certain panel data contexts In the current case, our interest is in nonlinear panel data models that cannot be estimated using linear methods We hold o¤ on discussing nonlinear panel ... nonlinear 3SLS If the demand functions are written in inverse form, the resulting system is linear in the parameters, as shown in Wooldridge (1996) 14.4 Panel Data Applications As we saw in Chapter ... absorbed in an intercept in x it Let wit contain cit , ci; tÀ1 , ait , and x it Then condition (14.48) holds, and l o and bo can be estimated by GMM Returning to condition (14.48), valid instruments...

Ngày tải lên: 06/07/2014, 08:20

... employment indicator and xj is a dummy variable indicating participation in a job training program, then expression (15.14) is the change in the probability of employment due to the job training program; ... approximate change in Pð y ¼ j zÞ given a percent increase in z2 Models with interactions among explanatory variables, including interactions between discrete and continuous variables, are handled similarly ... in school (status ¼ 0), not in school and not working (status ¼ 1), and working (status ¼ 2) The explanatory variables are education, a quadratic in past work experience, and a black binary indicator...

Ngày tải lên: 06/07/2014, 08:20

... test of the traditional Tobit random e¤ects model In data-censoring applications, our interest lies in b, and so—under the maintained assumptions—adding xi to the random e¤ects Tobit model solves ... support various kinds of data censoring Problem 16.3 asks you to consider general forms of data censoring, including the case when the censoring point can change with observation, in which case ... follows a Tobit model, and Tobit of y on x consistently estimates b and h s þ g t In data-censoring cases we are interested in b; g is of no use without observing q, and g cannot be estimated...

Ngày tải lên: 06/07/2014, 08:20

... context of two kinds of stratified sampling 17.8.1 Standard Stratified Sampling and Variable Probability Sampling The two most common kinds of stratification used in obtaining data sets in the social ... coin turning up heads in step depends only on the stratum ensures that sampling is random within each stratum This roughly reflects how samples are obtained for certain large cross- sectional and ... social sciences are standard stratified sampling (SS sampling) and variable probability sam- Sample Selection, Attrition, and Stratified Sampling 591 pling (VP sampling) In SS sampling, the population...

Ngày tải lên: 06/07/2014, 08:20