84,680 research outputs found
Orthogonal simple component analysis: A new, exploratory approach
Combining principles with pragmatism, a new approach and accompanying
algorithm are presented to a longstanding problem in applied statistics: the
interpretation of principal components. Following Rousson and Gasser [53 (2004)
539--555] @p250pt@ the ultimate goal is not to propose a method that leads
automatically to a unique solution, but rather to develop tools for assisting
the user in his or her choice of an interpretable solution. Accordingly, our
approach is essentially exploratory. Calling a vector 'simple' if it has small
integer elements, it poses the open question: @p250pt@ What sets of simply
interpretable orthogonal axes---if any---are angle-close to the principal
components of interest? its answer being presented in summary form as an
automated visual display of the solutions found, ordered in terms of overall
measures of simplicity, accuracy and star quality, from which the user may
choose. Here, 'star quality' refers to striking overall patterns in the sets of
axes found, deserving to be especially drawn to the user's attention precisely
because they have emerged from the data, rather than being imposed on it by
(implicitly) adopting a model. Indeed, other things being equal, explicit
models can be checked by seeing if their fits occur in our exploratory
analysis, as we illustrate. Requiring orthogonality, attractive visualization
and dimension reduction features of principal component analysis are retained.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS374 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
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Avoiding the Gaze of the Test: High Stakes Literacy Policy Implementation
This qualitative embedded case study documents the policy implementation of literacy assessment in a Texas urban high school, using Foucaultâs theory of the panopticon to understand how teaching and learning were shaped by the state high-stakes exit exam. In addition to the strong influence of the State of Texas Assessments of Academic Readiness (STAAR) test, data also indicated that despite an atmosphere of surveillance, teachers also worked strategically to make room for other types of literacy instruction. This was most visible in English I and II teachersâ commitment to process-based writing instruction focused on real-world text genres.Educatio
The role of pedagogical tools in active learning: a case for sense-making
Evidence from the research literature indicates that both audience response
systems (ARS) and guided inquiry worksheets (GIW) can lead to greater student
engagement, learning, and equity in the STEM classroom. We compare the use of
these two tools in large enrollment STEM courses delivered in different
contexts, one in biology and one in engineering. The instructors studied
utilized each of the active learning tools differently. In the biology course,
ARS questions were used mainly to check in with students and assess if they
were correctly interpreting and understanding worksheet questions. The
engineering course presented ARS questions that afforded students the
opportunity to apply learned concepts to new scenarios towards improving
students conceptual understanding. In the biology course, the GIWs were
primarily used in stand-alone activities, and most of the information necessary
for students to answer the questions was contained within the worksheet in a
context that aligned with a disciplinary model. In the engineering course, the
instructor intended for students to reference their lecture notes and rely on
their conceptual knowledge of fundamental principles from the previous ARS
class session in order to successfully answer the GIW questions. However, while
their specific implementation structures and practices differed, both
instructors used these tools to build towards the same basic disciplinary
thinking and sense-making processes of conceptual reasoning, quantitative
reasoning, and metacognitive thinking.Comment: 20 pages, 5 figure
Reinventing College Physics for Biologists: Explicating an epistemological curriculum
The University of Maryland Physics Education Research Group (UMd-PERG)
carried out a five-year research project to rethink, observe, and reform
introductory algebra-based (college) physics. This class is one of the Maryland
Physics Department's large service courses, serving primarily life-science
majors. After consultation with biologists, we re-focused the class on helping
the students learn to think scientifically -- to build coherence, think in
terms of mechanism, and to follow the implications of assumptions. We designed
the course to tap into students' productive conceptual and epistemological
resources, based on a theoretical framework from research on learning. The
reformed class retains its traditional structure in terms of time and
instructional personnel, but we modified existing best-practices curricular
materials, including Peer Instruction, Interactive Lecture Demonstrations, and
Tutorials. We provided class-controlled spaces for student collaboration, which
allowed us to observe and record students learning directly. We also scanned
all written homework and examinations, and we administered pre-post conceptual
and epistemological surveys. The reformed class enhanced the strong gains on
pre-post conceptual tests produced by the best-practices materials while
obtaining unprecedented pre-post gains on epistemological surveys instead of
the traditional losses.Comment: 35 pages including a 15 page appendix of supplementary material
Analytic Framework for Students' Use of Mathematics in Upper-Division Physics
Many students in upper-division physics courses struggle with the
mathematically sophisticated tools and techniques that are required for
advanced physics content. We have developed an analytical framework to assist
instructors and researchers in characterizing students' difficulties with
specific mathematical tools when solving the long and complex problems that are
characteristic of upper-division. In this paper, we present this framework,
including its motivation and development. We also describe an application of
the framework to investigations of student difficulties with direct integration
in electricity and magnetism (i.e., Coulomb's Law) and approximation methods in
classical mechanics (i.e., Taylor series). These investigations provide
examples of the types of difficulties encountered by advanced physics students,
as well as the utility of the framework for both researchers and instructors.Comment: 17 pages, 4 figures, 3 tables, in Phys. Rev. - PE
Polysemy and Co-predication
Many word forms in natural language are polysemous, but only some of them allow for co-predication, that is, they allow for simultaneous predications selecting for two different meanings or senses of a nominal in a sentence. In this paper, we try to explain (i) why some groups of senses allow co-predication and others do not, and (ii) how we interpret co-predicative sentences. The paper focuses on those groups of senses that allow co-predication in an especially robust and stable way. We argue, using these cases, but focusing particularly on the multiply polysemous word âschoolâ, that the senses involved in co-predication form especially robust activation packages, which allow hearers and readers to access all the different senses in interpretation
A comparison of integrated testlet and constructed-response question formats
Constructed-response (CR) questions are a mainstay of introductory physics
textbooks and exams. However, because of time, cost, and scoring reliability
constraints associated with this format, CR questions are being increasingly
replaced by multiple-choice (MC) questions in formal exams. The integrated
testlet (IT) is a recently-developed question structure designed to provide a
proxy of the pedagogical advantages of CR questions while procedurally
functioning as set of MC questions. ITs utilize an answer-until-correct
response format that provides immediate confirmatory or corrective feedback,
and they thus allow not only for the granting of partial credit in cases of
initially incorrect reasoning, but furthermore the ability to build cumulative
question structures. Here, we report on a study that directly compares the
functionality of ITs and CR questions in introductory physics exams. To do
this, CR questions were converted to concept-equivalent ITs, and both sets of
questions were deployed in midterm and final exams. We find that both question
types provide adequate discrimination between stronger and weaker students,
with CR questions discriminating slightly better than the ITs. Meanwhile, an
analysis of inter-rater scoring of the CR questions raises serious concerns
about the reliability of the granting of partial credit when this traditional
assessment technique is used in a realistic (but non optimized) setting.
Furthermore, we show evidence that partial credit is granted in a valid manner
in the ITs. Thus, together with consideration of the vastly reduced costs of
administering IT-based examinations compared to CR-based examinations, our
findings indicate that ITs are viable replacements for CR questions in formal
examinations where it is desirable to both assess concept integration and to
reward partial knowledge, while efficiently scoring examinations.Comment: 14 pages, 3 figures, with appendix. Accepted for publication in
PRST-PER (August 2014
A Pilot Study of Emotions of Writing in L2: Unpacking the Felt Sense of an EFL Writer
This study explores one EFL writerâs emotional aspects towards writing in second language (L2) through verbalizing her felt sense using the Thinking at the Edge (TAE) approach. Data collected include the participantâs autobiography of learning English, TAE-based reflective worksheets, and an individual interview. To analyze the data, thematic analysis (Boyatzis, 1998) in a qualitative method was employed. The findings reveal that the participant showed difficulty in expressing herself clearly in English and remained apprehensive about using English words and expressions properly. However, she realized the importance of English writing, which has promoted her creating a sense of confidence and writing proficiency. This study indicates that the findings obtained by the TAE approach will enhance the importance of seeking learnersâ psychological engagement with writing in L2 in a qualitative manner
Assessment in anatomy
From an educational perspective, a very important problem is that of assessment, for establishing competency and as selection criterion for different professional purposes. Among the issues to be addressed are the methods of assessment and/or the type of tests, the range of scores, or the definition of honour degrees. The methods of assessment comprise such different forms such as the spotter examination, short or long essay questions, short answer questions, true-false questions, single best answer questions, multiple choice questions, extended match questions, or several forms of oral approaches such as viva voce examinations.Knowledge about this is important when assessing different educational objectives; assessing educational objectives from the cognitive domain will need different assessment instruments than assessing educational objectives from the psychomotor domain or even the affective domain.There is no golden rule, which type of assessment instrument or format will be the best in measuring certain educational objectives; but one has to respect that there is no assessment instrument, which is capable to assess educational objectives from all domains of educational objectives.Whereas the first two or three levels of progress can be assessed by well-structured written examinations such as multiple choice questions, or multiple answer questions, other and higher level progresses need other instruments, such as a thesis, or direct observation.This is no issue at all in assessment tools, where the students are required to select the appropriate answer from a given set of choices, as in true false questions, MCQ, EMQ, etc. The standard setting is done in these cases by the selection of the true answer
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