Judul: Selang kepercayaan untuk koefisien B1 dari garis regresi apabila ragam galat tidak homogen dengan metode ols, wls dan bootstrap
Abstrak: Slope estimation of a regression line and its confidence interval can be constructed by OLS (Ordinary Least Squares) and WLS (Weighted Least Squares) method. Confidence interval being found by both method must satisfy assumption about normality of error term with zero mean and common variance for OLS method and heteroscedasticity for WLS method and independency of error term. NC (Nanayakkara and Cressie) method is a method aimed to reduce variance of estimate resulted from OLS method when error term has non- constant variance.
Keyword: Percentite-bootstrap, Ordinary Least Squares, Weighted Least Squares

Judul: Perbandingan Metode MKT, LTS, WIN, dan Theil pada Pendugaan Parameter Regresi Apabila Galatnya Menyebar Eksponensial
Abstrak: Parameter estimation in simple linear regression analysis can be done with Ordinary Least Square (OLS). This method requires the assumption that error must be Normally distributed. However, in reality error is not always Normally distributed, but has another distribution, for example Exponential. Concequently, parameter estimation by MKT is not optimal. This problem can be solved by applying robust regression. This research applied Least Trimmed Square (LTS) method, Winsorized Least Square (WIN) method, and Theil’s method as a solution. The data used in this study was simulation data. Explanatory variables (x) is generated from the Normal distribution, while the error generated from the Exponential distribution. The results of estimation are evaluated with MSE and Relative MSE. The results showed that LTS was the best method when the error is Exponentially distributed.
Keyword: Bogor Agricultural University (IPB), WIN, Theil’s Method, OLS, LTS

Judul: Studi Taksonomi Katak Subgenus Papurana (Lesson, 1831) dari Halmahera (Anura, Ranidae, Hylarana), Studi Taksonomi Katak Subgenus Papurana (Lesson, 1831) dari Halmahera (Anura, Ranidae, Hylarana
Abstrak: I reevaluated taxonomic of subgenus Papurana position from Halmahera based on morphological and molecular analyses. My results show that two separate species occur on the Halmahera Island, each nested within two distinct clades (hereafter papua clade and celebensis clade), one of which corresponds to H. moluccana (celebensis clade) and the other to an unidentified species (papua clade). By p-distance ranging from 6.9 to 11.5% on the 16S rRNA gene, the unidentified species (Hylarana sp.) is genetically different from all congeners of the papua clade. The Hylarana sp. can be distinguished from all congeners by following combination of charactes: vomer teeth in two oblique rows with narrow inter-vomer distance; snout rounded dorsally; dorsum with few scattered cone-shaped tubercles that are black with white tips; distinct skin folds (ridges) on the dorsal side of the thigh coinciding with dark brown cross bars; a marbled pattern on the ventral side of the thigh and yellowish groin. I also present new data for H. daemeli, H. volkerjane, and H. arfaki from the western region of Papua. Furthermore, I found that H. celebensis has numerous mtDNA lineages, indicating cryptic diversity within the celebensis clade. The discovery of two separate species on Halmahera necessitates more research into the biogeographic history of Hylarana in Northern Moluccas.
Keyword: frog, Halmahera, Hylarana, morphology, Papurana, phylogenetic