Judul: Statistical Analysis for Non-Normal and Correlated Outcome in Panel Data
Abstrak: There are many cases that cannot fulfill some assumptions in statistical analysis, such as normality and independence. In many practical problems, the normality as well independent assumption is not reasonable. For example, data that repeated over time tend to be correlated. If analysis ignores the non independent outcome the Standard Error (SE) on the parameter estimates tends to be too small. Generalized Linear Model (GLM), Generalized Estimating Equation (GEE), and Generalized Linear Mixed Model (GLMM) can be used for nonnormal data using the link functions. GEE includes working correlation matrix to accommodate the correlation in the data. GLMM may overcome the repeated observation and allows individual have different baseline/intercept. The study is aim at comparing result based on those approaches. The data that are used in this study are from BPS and the outcome that are used is poverty proportion. Based on the study shows that GEE approach is better than GLM for marginal model, and GLMM approach is better than GEE with dummy variable.
Keyword: Bogor Agricultural University (IPB), non-normal, GLMM, GLM, GEE, correlation outcome

Judul: Parameter Estimation Of Correlated Outcome And Covariates Measured With Error In Logistic Regression
Abstrak: In epidemiological studies, it is common to have binary data as the response variable. Hence, the common model applied to represent the relationship between the binary outcome and risk factors is logistic regression. Problems that commonly occur in binary data are intra-class correlation in the outcome variable and measurement error or misclassification in the covariates/risk factors. An alternative statistical procedures, William's procedure and Generalized Estimating Equation for correlated outcome and direct adjustment for measurement error, are used to handle these problems. The application of these methods is implemented to the Children Nutrient Status Data. The data is obtained from the study conducted in June 2000 - October 2000, involving 402 children under five years old in three locations in Central Java. In the analysis of intra-enumerator data, there is an indication of the presence of intra-correlation between data co llected and enumerator.
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Judul: Elektrodeposisi Film Tipis Semikonduktor Cu2ZnSnS4 (CZTS) pada Substrat Kaca ITO
Abstrak: Semiconductor Cu2ZnSnS4 (CZTS) thin film that can be used as absorber layers on solar cell module was made via electrodeposition method. CZTS thin film was electrodeposited on the surface of a silicate glass coated with a thin layer of indium tin oxide (ITO). Deposition process was done using potentiostatic mode at room temperature with a potential of 1.05 V for 30, 45, and 60 minutes, followed with annealing the film at 2 different temperatures, 500 ºC using furnace and 180 ºC using hot plate, both treatments for 45 minutes in N2/H2S atmosphere. The X-ray difractograms were analyzed using Match 2 program and showed that the CZTS thin films had kesterit crystalline structure, with a low percentage of CZTS phase. The thin film also contained secondary phases such as Cu2S, ZnS, and SnS. The obtained CZTS thin films had a thickness between 1.039 and 1.676 μm. Absorption study showed that the band gap energy of CZTS thin films which was annealed using furnace ranged from 1.50 to 1.52 eV, whereas that annealed using the hot plate was not observed. The band gap energy value showed that CZTS thin films can be used as sunlight absorber layers on solar cell. The formation of CZTS crystal film on this investigation was effectively performed using furnace annealing process at a temperature of 500 ºC with deposition time of 45 minutes.
Keyword: Thin film, Electrodeposition, Cu2ZnSnS4