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Title: The Robust Test Statistic in Comparing Two Independent Groups using Trimming and Winsorization
Author(s): Suhaida Abdullah, Sharipah Soaad Syed Yahaya, Zahayu Md. Yusof
Pages: 1-6 Paper ID:172206-5454-IJBAS-IJENS Published: December, 2017
Abstract: The classical independent t-test is often in jeopardy when the assumptions of normality or homogeneity of variances being violated. The test performs worsen when these violations occur simultaneously. Alexander-Govern test offers the alternative solution to the classical t-test when dealing with heterogeneous variances conditions. However, it produces good control of Type I error rates only if the data are normally distributed, which is a known fact that normality is hardly achieved in real life situation. As a remedy, in this study, we modify the Alexander-Govern test using trimmed mean and Winsorized mean as the location measures. Generally, the modified test using trimmed mean performs better compared to the original test in terms of Type I error rates. However, the test using Winsorized mean failed to control the Type I error rate well under most condition considered.
Keywords: T-test; Alexander-Govern test; trimmed mean; Winsorized mean.
Full Text (.pdf)  International Journals Of Engineering and Science | 341 KB
Title: Improving Teaching Skills Through Learning Model Development Microteaching Based on Experimental Learning
Author(s): Yudi Supiyanto, Dumiyati, Henny Sulistyoningrum
Pages: 7-11 Paper ID:172606-3131-IJBAS-IJENS Published: December, 2017
Abstract: The aim of this research is to develop the implementation of experiential learning model of microteaching learning through the role of model and cooperative group in the microteaching course and to develop a set of instruments needed to assess the validity, practicalities and effectiveness of the developed learn-ing model. Development of experiential learning-based micro-teaching learning model uses the stages of learning model Plomp ( 1997) but researchers only use 4 stages namely: a) in-itial assessment phase, b) design stage, c) realization / construc-tion stage, d) test phase, evaluation and revision. The subjects of the study were the students of the Education Economics Faculty of Teacher Training and Education of the University of PGRI Ronggolawe Tuban in the sixth semester who took Mi-croteaching courses and in the seventh semester took the Field Teaching Practice 2. Data collection was done by questionnaire, observation and documentation. The data were analyzed by descriptive technique. The results of this study indicate that: 1) development learning tools included in good category and can be used, 2) instrument of assessment instrument of micro-teaching model based on Experiential Learning result of devel-opment (teaching book valuation instrument, lesson plan, stu-dent activity sheet assessment and assessment of modeling) in-cluded good category
Keywords: ---
Full Text (.pdf)  International Journals Of Engineering and Science | 195 KB
Title: Effect of Ni-doping on Structure and Morphology of La0.7Ba0.3Mn1-xNixO3 Compounds by Sol-Gel Method
Author(s): Sitti Ahmiatri Saptari, Arif Tjahjono, Suci Winarsih, Putranto Prasetyo, Budhy Kurniawan
Pages: 12-16 Paper ID:173406-5959-IJBAS-IJENS Published: December, 2017
Abstract: This paper concerned to explain about the effect of Ni-doping on structure and morphology of La0.7Ba0.3Mn1-xNixO3 (x=0; 0.1; 0.2; 0.3) compounds. In this study, we prepared our sample through the sol-gel method with precursors La2O3, Ba(NO3)2, Mn(NO3)2.4H2O, and Ni(NO3)2.6H2O. The crystal structure and morphology samples were characterized by X-Ray Diffraction (XRD) and SEM-EDX. Refinement results showed that all samples were single phase and formed a rhombohedral crystal structure with space group R-3c. The effect of Ni-doping on the structure did not make phase changing, but the lattice parameter c of La0.7Ba0.3Mn1-xNixO3 compounds decreased very slightly as Ni-doping increased. Microstructure of La0.7Ba0.3Mn1-xNixO3 observed by Scanning Electron Microscope (SEM) indicated that the microstructures were homogeneous with nanoparticle size. The result micro analysis by EDX (Energy Dispersive X-Ray) assured phase from XRD result.
Keywords: La0.7Ba0.3Mn1-xNixO3, Ni-doping, structure, morphology, sol-gel method
Full Text (.pdf)  International Journals Of Engineering and Science | 504 KB