Statistical user interfaces

A statistical user interface is an interface between a human user and a statistical software package. Whenever we use a statistical software package we want to solve a specific statistical problem. But very often at first it is necessary to learn specific things about the software package. Everyone of us knows about the ?religious wars? concerning the question which statistical software package/method is the best for a certain task; see Marron (1996) and Cleveland and Loader (1996) and related internet discussions. Experienced statisticians use a bunch of different statistical software packages rather than a single one; although all of the major companies (at least the marketing departments) tell us that we only need their software package. --

Visualizing exploratory factor analysis models

Exploratory factor analysis (EFA) is an important tool in data analyses, particularly in social science. Usually four steps are carried out which contain a large number of options. One important option is the number of factors and the association of variables with a factor. Our tools aim to visualize various models with different numbers in parallel of factors and to analyze which consequences a specific option has.We apply our method to data collected at the School of Business and Economics for evaluation of lectures by students. These data were analyzed by Zhou (2004) and Reichelt (2007).Factor analysis, visualization, questionnaire, evaluation of teaching

Embedding R in the Mediawiki

Teaching statistics to students in our area of economics and educational science often brings about the problem that students have either forgottentheir statistical knowledge, or have taken different classes than the ones we offer in basic statistics. We therefore need some kind of statistical dictionary where we, as teachers, can refer to a common base and where students can look up specific terms. The Wikipedia - a general online encyclopaedia - compelled us to use a wiki for our dictionary. While the Wikipedia contains a large number of statistical terms, these are often too long and detailed to be visual displayed in lectures very well and some more specific terms are not included.R, wiki, Mediawiki

Interaction of solid organic acids with carbon nanotube field effect transistors

A series of solid organic acids were used to p-dope carbon nanotubes. The extent of doping is shown to be dependent on the pKa value of the acids. Highly fluorinated carboxylic acids and sulfonic acids are very effective in shifting the threshold voltage and making carbon nanotube field effect transistors to be more p-type devices. Weaker acids like phosphonic or hydroxamic acids had less effect. The doping of the devices was accompanied by a reduction of the hysteresis in the transfer characteristics. In-solution doping survives standard fabrication processes and renders p-doped carbon nanotube field effect transistors with good transport characteristics.Comment: 5 pages, 4 figures, 1 tabl

Thermodynamic calculations on the catalytic growth of multiwall carbon nanotubes

We have developed a thermodynamic model of the catalytic growth of multiwall carbon nanotubes from hydrocarbon precursors at elevated temperature. Using this model we have computed the heat distribution, and carbon concentration in the catalyst. Calculations delivered a analytical formula for the growth time and growth rate. We find that the growth is mainly driven by a concentration gradient within the catalyst, rather than a temperature gradient.Comment: 9 pages, 3 figures, 1 tabl

Integrable e-lements for Statistics Education

Without doubt modern education in statistics must involve practical, computer-based data analysis but the question arises whether and how computational elements should be integrated into the canon of methodological education. Should the student see and study high-level programming code right at the beginning of his or her studies? Which technology can be presented during class and which computational elements can re-occur (at increasing level of complexity) during the different courses? In this paper we address these questions and discuss where e-techniques have their limits in statistics education.electronic books, hypertext, e-supported teaching, statistical software

Yxilon – a Modular Open-Source Statistical Programming Language

Statistical research has always been at the edge of available computing power. Huge datasets, e.g in DataMining or Quantitative Finance, and computationally intensive techniques, e.g. bootstrap methods, always require a little bit more computing power than is currently available. But the most popular statistical programming language R, as well as statistical programming languages like S or XploRe, are interpreted which makes them slow in computing intensive areas. The common solution is to implement these routines in low-level programming languages like C/C++ or Fortran and subsequently integrate them as dynamic linked libraries (DLL) or shared object libraries (SO) in the statistical programming language.statistical programming language, XploRe, Yxilon, Java, dynamic linked libraries, shared object libraries

Yxilon – A Client/Server Based Statistical Environment

Along with many others, we agree that a modern education in statistics needs to incorporate the practical analysis of real datasets, which are usually more complex than the common examples found in standard textbooks. The software used in the teaching of statistics includes standard spreadsheet environments such as OpenOffice and Excel and dedicated commercial and non-commercial packages such as R, Minitab or SPSS. With the freely available Yxilon environment we add another package and proliferate the statistical programming language XploRe, using a modern client/server based architecture. This architecture has the capabilities of serving statistical results in a variety of flavors for different groups of users. In this paper we describe the general setup of the Yxilon environment and present selected technical details.E-learning, Statistical Software.

Using Wiki to Build an E-learning System in Statistics in Arabic Language

E-learning plays an important role in education as it supports online education via computer networks and provides educational services by utilising information technologies. We present a case study describing the development of an Arabic language elearning course in statistics. Discussed are issues concerning e-learning in Arab countries with special focus on problems of the application of e-learning in the Arab world and the difficulties concerning the design Arabic platforms such as language problems, cultural and technical problems, especially ArabTeX works difficulty with LaTeX format. Thus Wiki is offered as a solution to such problems. Wiki supports LaTeX and other statistical programs, for instance R, and^Wiki offers the solution to language problems. Details of this technology are discussed and a solution as to how this system can serve in building an Arab platform is presented.E-Learning, MM*Stat, Wiki, ArabTeX, Statistical Software.