Judul: Kajian Metode Dalil Limit Pusat, Transformasi, dan Resampling Bootstrap dalam Penentuan Selang Kepercayaan
Abstrak: Selang kepercayaan biasanya dibangun berdasarkan asumsi normalitas. Padahal banyak data dalam dunia nyata tidak menyebar normal. Contoh data yang sebarannya menjulur yaitu data yang menyebar khi-kuadrat dan generalized extreme value (GEV). Selang kepercayaan bagi data tersebut dapat menerapkan metode dalil limit pusat, transformasi, dan bootstrap. Keunggulan dari ketiga metode tersebut dalam menghasilkan selang kepercayaan bagi parameter nilai tengah dapat dievaluasi berdasarkan nilai keakuratan selang kepercayaan, lebar selang, dan simpangan baku lebar selang yang dihasilkan. Metode dikatakan baik apabila mampu menghasilkan nilai keakuratan tinggi, rata-rata lebar selang dan simpangan baku lebar selang yang kecil. Data yang digunakan dalam penelitian ini terdiri dari data simulasi dan data riil. Data simulasi dibangkitkan dari sebaran khi-kuadrat, GEV, dan sebaran normal yang dimodifikasi agar tidak menyebar normal dengan mentransformasi data dengan transformasi kuadrat dan transformasi logaritma. Hasil menunjukkan bahwa metode transformasi baik digunakan ketika ukuran contoh kecil. Metode dalil limit pusat dan metode bootstrap lebih baik digunakan ketika ukuran contoh besar.
Keyword: dalil limit pusat, bootstrap, selang kepercayaan, transformasi

Judul: Pendugaan Selang Kepercayaan Bootstrap bagi Ukuran Pemusatan Data Sirkular
Abstrak: The confidence interval is an estimator based on the sampling distribution. When the sampling distribution can not be derived from population distribution, the bootstrap method can be used to estimate it. Three methods used to estimate the bootstrap confidence interval for circular data were equal-tailed arc (ETA), symmetric arc (SYMA), and likelihood-based arc (LBA). In this study, three methods were evaluated through simulation study. The most important criterion to evaluate them were true coverage and interval width. The simulation results indicated in all methods, the interval width shortened when the concentration parameter increased. True coverage approached confidence level when the concentration parameter were one or more. For small concentration parameter, all three methods appeared unstable. Based on the true coverage, SYMA was the best, while in terms the interval width, LBA was the best one. For both criterion could be summarized that ETA is the best result. ETA and SYMA applicated for estimate the period of Dengue Fever outbreaks in Bengkulu. The estimation showed that Dengue Fever outbreaks in 2009 were October through January. In 2010, it were January through March, and in 2011, it were June through September.
Keyword: 

Judul: Insecticidal Activity of Essential Oils Leaves of Cinnamomum spp. (Lauraceae) against Crocidolomia pavonana and Their Phytotoxicity on Broccoli Seedlings
Abstrak: Essential oils from leaves of 13 species of Cinnamomum were tested for their insecticidal activity on the cabbage head caterpillar Crocidolomia pavonana with leaf immerse method. The results showed that the treatment with 1% (w/v) essential oils leaves of C. celebicum, C. multiflorum, C. sintoc, and C. verum caused 21.45, 93.65, 60.30, and 76.10% mortality, respectively. Based on the results of phytotoxicity and insecticidal activity tests, C. multiflorum oil was further tested at 6 concentration levels. In all treatments, larval mortality has occurred at 24 hours after treatment (HAT) and increased at 48 HAT. LC50 of C. multiflorum oil at 24 and 48 HAT was 0.504 and 0.396%, respectively. The treatment with C. multiflorum oil at ≤0.31% did not inhibit the development of C. pavonana larvae. Determination of the chemical constituents of Cinnamomum oils were carried out by gas chromatography-mass spectrometry (GCMS). Totally, 345 compounds were identified. Methyleugenol constituted the main component (49.4%) of leaf essential oil of C. multiflorum and was assumed to be responsible for the insecticidal activity of the oil against C. pavonana larvae. LC50 of pure methyleugenol obtained at 0.365% (48 HAT) and 0.363% (72 HAT). The results showed that C. multiflorum was more effective with LC50 value equivalent to methyleugenol content of 0.32% (24 HAT) and 0.24% (48 HAT).
Keyword: