On the student evaluation of university courses and faculty members’ teaching performance

Trying to determine higher education quality, one gets quickly to one of its significant dimensions, namely the quality of faculty members’ teaching. The latter and, overall, the quality of any university course should be certainly evaluated by their recipients, namely students. In this paper we develop a statistical framework based on Statistical Quality Control mainly, which can be used in order to exploit student evaluations as much as possible. More specifically we present two directions of data monitoring and analysis; the one uses control charts and the other hypotheses testing. The results that can be raised through both directions are crucial for any decision maker.     

e-Statistics for deriving QSAR models

This paper presents some freeware, shareware, and commercial statistical tools available via the Internet and which could be used in QSAR for deriving models. Programming environments useful in Statistics, newsgroups and FAQs are also introduced due to their interest for the discipline.     

Spectrophotometric determination of Rare Earth Elements in aqueous nitric acid solutions for process control

Noninvasive analytical control is of special interest for the complicated and hazardous production processes. On-line monitoring provides a unique opportunity to determine critical concentrations rapidly and without serious risks to operating personnel and the environment. Models for quantitative determination of concentrations of Rare Earth Elements in complex mixtures in nitric acid serve for these purposes. Here, the feasibility of simultaneous determination of cerium, praseodymium, and neodymium using the whole UV–vis spectroscopic range, together with chemometric data processing, is studied. The predictability of two chemometric techniques, partial least squares regression and correlation constrained multivariate curve resolution–alternating least squares are compared. Models’ performances are analyzed in out-of-control cases.     

具有未知误差方差的多元正态线性模型中回归系数的所有k-容许估计

考虑多元线性模型Ｙ～Ｎ（ＸΘ，σ２ＩｍＶ），和ＳＸΘ的估计问题，取损失函数为（σ－ＳＸΘ）′（δ－ＳＸΘ），本文定义所谓的ｋ－容许性和Φ（ｋ）－容许性．本文在一定条件下得到了ＳＸΘ的线性估计ＬＹ＋Ｄ在一切估计类中ｋ－容许和Φ（ｋ）－容许的充要条件．一般情况下得到了充分条件和必要条件．     

An investigation of statistical thinking in two different contexts: Detecting a signal in a noisy process and determining a typical value

The study describes students’ patterns of thinking for statistical problems set in two different contexts. Fifteen students representing a wide range of experiences with high school mathematics participated in problem-solving clinical interview sessions. At one point during the interviews, each solved a problem that involved determining the typical value within a set of incomes. At another point, they solved a problem set in a signal-versus-noise context [Konold, C., & Pollatsek, A. (2002). Data analysis as the search for signals in noisy processes. Journal for Research in Mathematics Education, 33, 259-289]. Several patterns of thinking emerged in the responses to each task. In responding to the two tasks, some students attempted to incorporate formal measures, while others used informal estimating strategies. The different types of thinking employed in using formal measures and informal estimates are described. The types of thinking exhibited in the signal-versus-noise context are then compared against those in the typical value context. Students displayed varying amounts of attention to both data and context in formulating responses to both problems. Suggestions for teachers in regard to helping students attend to both data and context when analyzing statistical data are given.     

Simultaneous multielemental determination using a low-resolution inductively coupled plasma spectrometer/diode array detection system

This work presents a versatile method for simultaneous multielemental analysis using detection with photodiode arrays and multivariate calibration techniques. A multidetection system based on an array of 1024 photodiodes was built and adapted to a commercial plasma emission scanning spectrometer. Spectral data were acquired at low resolution, allowing simultaneous monitoring of a broad spectral range and resulting in very informative but considerably overlapped spectra. Partial least squares and principal component regressions were employed to minimize overlapping problems. A numerical procedure for window selection was also developed.

The new method was applied to the simultaneous determination of manganese, molybdenum, nickel, chromium and iron in steel samples, resulting in average relative prediction errors of 2.1% for Mn, 3.4% for Mo, 0.6% for Cr, 1.5% for Ni and 0.8% for Fe. These errors are comparable to those observed with conventional scanning detection systems and separate univariate calibrations, but the new method allows simultaneous determination of the five elements, with data acquisition significantly faster than in scanning instruments.     

Asymptotic Normality of the Recursive M-estimators of the Scale Parameters

In this paper, the limit distributions of the recursive M-estimators of scatter parameters in a multivariate linear model setting are studied. Under some mild conditions, the asymptotic normality of the recursive M-esimtators is established. Some Monte Carlo simulation results are presented to illustrate the performance of the recursive M-estimators.