Judul: Perbandingan Uji Reliabilitas Cronbach Alpha untuk Data Berskala Rasio dan Ordinal
Abstrak: A reliability test is often performed on survey data. The goal is to determine the data characteristics both in terms of consistency and accuracy. The reliability test has a condition that to be satisfied, i.e., the data must be continuous (ratio), while the data obtained from a survey is commonly an ordinal type. This paper aims to measure the magnitude of the bias related to reliability test and the patterns of alleged bias related to the number of categories and the number of data samples surveyed. It was shown in this work, as the number of categorized ordinal data and the number of sample data increase, the amount of bias decreases. It was also shown that by assigning 6 categories ordinal data scales and the number of data sample was 400, the level of bias would be not more than 5%.
Keyword: Bogor Agricultural University (IPB), reliability test., ratio scale, ordinal scale

Judul: Beberapa uji keterandalan kuesioner
Abstrak: Penelitian ini bertujuan untuk menganalisis keterandalan beberapa topik pada kuesioner dengan menggunakan lima metode, yaitu metode Cronbach Alpha, Spearman-Brown, Guttman, Rulon dan Analisis Ragam. Di samping itu dalam penelitian ini juga dianalisis kehomogenan dan konsistensi internal antar butir pertanyaan dari topik-topiknya. Data yang digunakan dalam penelitian ini diperoleh mahasiswa Tingkat Persiapan Bersama, Institut Pertanian Bogor, Kelompok V. dengan menggunakan kuesioner. Kuesioner yang digunakan berisi delapan belas butir pertanyaan, terdiri dari dua topik. Topik pertama berisi pertanyaan-pertanyaan tentang Evaluasi Mahasiswa Terhadap Dosen Matematika I, sedangkan topik kedua berisi pertanyaan-pertanyaan tentang Evaluasi Mahasiswa Terhadap Asisten Matematika I. Skor yang diberikan terhadap masing-masing butir pertanyaan ditetapkan berdasarkan skala pengukuran ordinal. Penarikan contoh dilakukan secara acak sebanyak 33 orang responden. Kehomogenan antar butir pertanyaan pada kedua topik yang dianalisis cukup tinggi, karena keragaman antar butir pertanyaannya sebagian besar berada pada kategori rendah.
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Judul: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition