Free Statistics Journal

Impact of Resource Conservation Technologies for Sustainability of Irrigated Agriculture in Punjab-Pakistan

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 23:26:00 +0700

Muhammad Rafiq Akhtar

Director, Agricultural Information, Punjab, Lahore (Pakistan).

Abstract
Pakistan is rightly proclaimed as an agricultural country. Agriculture is the largest commodity producing sector and mainstay of the country’s economy. Wheat as a main staple food crop of Pakistan is grown on about 8 million hectares every year. It is a Rabi (winter) crop and replaces rice and cotton in rice-wheat and cotton-wheat systems, respectively. Rice and cotton is grown on 2.4 and 2.9 million hectares every year, respectively. Pakistan’s population is increasing at an alarming pace and it has reached to about 150 million already. Resultantly, with the exception of few years, Pakistan had to import wheat from international market on expense of huge foreign exchange to meet food requirements of its burgeoning population. It is, therefore, imperative to enhance wheat yield by encouraging farmers, predominantly small farmers, to grow more wheat
with efficient and judicious use of land and water resources. Land and water resources especially for agricultural purposes are getting scarce day by day due to mismanagement. This water deficient scenario is also posing serious threats to food security for generations to come. A shift in the production techniques intervening flooded irrigation methods for efficient utilization of resources is being recommended and same has been actively adopted in many courtiers of South Asia. The resource conservation technologies (RCTs) mainly include bed planting of wheat, sowing of wheat following zero tillage technology, bed and furrow sowing of cotton and management of crop residues. Laser land leveling adopted in Pakistan has shown encouraging results under zero tillage technique wheat is sown using residual moisture with no or minimum tillage without irrigating the fields with the aim to sow wheat in time after rice, conservation of water, and reduced cultivation cost. The technology has been adopted on about one million hectares and presently farmers own more than 5,000 zero tillage drills. Similarly, crops especially cotton is being planted on the raised beds to minimize water losses caused in the flood irrigations. Although these technologies are being adopted on wide scale, yet some quarters are still showing their concerns regarding weed control, pest management and impact on soil structure in relation to adoption of such technology in rice-wheat system of the Punjab. Other faction of scientists/experts is advocating adoption of zero tillage in the country because of embedded benefits of these technologies; for example, efficient use of water and other inputs, cost effectiveness compared to conventional methods of sowing, reduced consumption of diesel and above all, advancement of planting date of wheat by reducing turn around time between wheat sowing and successive rice crop. Latest dimensions of zero tillage and bed planting are also being highlighted in favour of this technology including improving soil biodiversity, reduced air pollution, mitigation of environmental degradation after residue burning, and carbon sequestration.

Keywords: Irrigated farming; sustainability; resource conservation; productivity; Punjab; Pakistan.

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Effects of Storage of Bananas in Controlled Atmosphere Before Ethylene Treatments on Its Ripening and Quality

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 23:19:00 +0700

Saeed Ahmad

Ph.D. Study, Cranfield University, UK.,

M. A. Perviez

Assistant Research Officer,

A. K. Thompson

Institute of Horticultural Sciences, University of Agriculture Faisalabad.,

and Hammed Ullah

Citrus Research Station, Sahiwal.

Abstract

The study was conducted in Post Harvest Laboratory, Cranfield University at Silsoe College, UK during 1999. The objective was to investigate whether ripening processes in banana fruits which are depressed in reduced O2 and increased CO2 storage for two weeks, could be initiated with ethylene treatment and produce good quality ripe fruit like control. It was observed that ethylene treatment became dominant over the inhibition effect of controlled atmosphere storage when bananas were removed to normal air. All bananas including control reached colour stage 6 after 9 days of ethylene treatment. Bananas exhibited the lowest weight loss at 2 percent O2 with 8, 6 and 4 percent CO2 while the control showed higher percentage of weight loss during storage. The trend of weight loss was changed during ripening which was less in storage conditions but it increased with ethylene treatments. The total weight loss (storage + ripening) was greater (5.48%) in control and it was lower (4.71, 4.54 and 4.68%) in storage at 2 percent O2 with three levels of CO2. Controlled atmosphere storage showed no effect on total soluble solids. Bananas stored at 2 percent O2 with 4, 6 and 8 percent CO2 produced firm bananas (3.48, 5.51 and 3.54 values N/mm). Firm and ripe bananas could be less susceptible to mechanical injury and some fungal diseases.

Keywords: Bananas; controlled atmosphere storage; oxygen; carbon dioxide; chlorothalonil; United Kingdom.

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Green Fodder Yield Performance of Oats Varieties Under Irrigated Conditions

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 23:15:00 +0700

Muhammad Naeem

Senior Scientific Officer, National Cooperative Research Programme on Fodder Crops,

Muhammad Shahid Munir Chohan, Ahmad Hassan Khan

Assistant Research Officer,

and Riaz Ahmad Kainth

Assistant Botanist, Fodder Research Sub-Station,

AyubAgricultural Research Institute, Faisalabad, Pakistan.

Abstract

Nine varieties of oats and a check were evaluated during rabi season 2002-03 at Fodder Research Sub-station, Ayub Agricultural Research Institute, Faisalabad. Significant differences were observed for plant height, number of tillers per meter row and green fodder yield while differences for number of leaves per tiller and leaf area were non-significant. The variety S-81 was the tallest (103.33 cm) while check variety PD2 LV65 the shortest (86 cm). Number of tillers per meter row varied from 79 (check PD2 LV65) to 106.67 (S-81) while number of leaves per tiller ranged from 7.89 (PD2 LV65) to 9 (S-81, Scott, No.708 and S-2000). Leaf area varied from 70.38 (No.681) to 84.96 cm2 (Scott) while green fodder yield ranged from 49.36 (check PD2 LV65) to 69.44 tons per hectare (S-81). Varieties Scott and No.708 ranked second by producing identical green fodder yield (66.98 t/ha) followed by No.677 (66.67 t/ha), S-2000 (65.43 t/ha) and No.681 (63.89 t/ha).

Keywords: Avena sativa; high yielding varieties; agronomic characters; performance; Pakistan.

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Comparison of some Advanced Lines of Sorghum Bicolor L. Monech for Green Fodder/Dry Matter Yields and Morpho-Economic Parameters

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 22:41:00 +0700

Chaudhry Ghulam Nabi, Muhammad Riaz and Ghulam Ahmad

Fodder Research Institute, Sargodha, Pakistan.

Abstract
These studies were conducted at Fodder Research Institute, Sargodha during the year 1999-2001. Five cultivars of sorghum including check (Hegari) were evaluated for plant height, stem thickness, leaf area, number of leaves per plant, sweetness, crude protein, green fodder and dry matter yields. Cultivar JS-88 showed significant differences with higher number of leaves per plant (13.5), stem thickness (1.8 cm) and leaf area (512.5 cm2) as compared to check (10.6 average number of leaves/plant, 1.3 cm stem thickness and 445.5 cm2 leaf area). Similarly, JS-88 was superior in green fodder yield, dry matter yield and quality (sweetness and crude protein) to Hegari. On an average JS-88 produced 73.8 tons per hectare green fodder and 12.8 tons per hectare dry matter yield as compared to Hegari (59.6 t/ha green fodder yield and 8.4 t/ha dry matter yield). Early growth stages had high crude protein level than late stages.

KEYWORDS: Sorghum bicolor; high yielding varieties; agronomic characters; Pakistan.

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The predictive power of the European Economic Sentiment Indicator

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 22:28:00 +0700

Sarah Gelper and Christophe Croux

Abstract
Economic sentiment surveys are carried out by all European Union member states on a monthly basis. The survey outcomes are used to obtain early insight into future economic evolutions and often receive extensive press coverage. Based on these surveys, the European Commission constructs an aggregate European Economic Sentiment Indicator (ESI). This paper compares the ESI with more sophisticated aggregation schemes based on two statistical methods: dynamic factor analysis and partial least squares. We compare the aggregate sentiment indicators and the weights used in their construction. Afterwards a comparison of their forecast performance for two real economic series, industrial production growth and unemployment, follows. Our findings are twofold. First it is found that the ESI, although constructed in a rather ad hoc way, can compete with the indicators constructed according to statistical principles. Secondly, the predictive power of the sentiment indicators, as tested for in an out-of sample Granger causality framework, is limited.

Keywords: Common indicators; Dimension reduction methods; Economic sentiment indicator; Forecasting.

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Modeling a healthcare system as a queueing network:The case of a Belgian hospital

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 22:25:00 +0700

Creemers S and Lambrecht MR

Abstract

The performance of health care systems in terms of patient flow times and utilization of critical resources can be assessed through queueing and simulation models. We model the orthopaedic department of the Middelheim hospital (Antwerpen, Belgium) focusing on the impact of outages (preemptive and nonpreemptive outages) on the effective utilization of resources and on the flowtime of patients. Several queueing network solution procedures are developed such as the decomposition and Brownian motion approaches. Simulation is used as a validation tool. We present new approaches to model outages. The model offers a valuable tool to study the trade-off between the capacity structure, sources of variability and patient flow times.

Keywords: Belgium; Brownian motion; Capacity management; Decomposition; Health care; Healthcare; Impact; Model; Models; Performance; Performance measurement; Queueing; Queueing theory; Simulation; Stochastic processes; Structure; Studies; Systems; Time; Tool; Validation; Variability.

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callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 22:20:00 +0700

Brecht Cardoen, Erik Demeulemeester, Jeroen BeliÄen
Katholieke Universiteit Leuven, Faculty of Economics and Applied Economics, Department of Decision Sciences and Information Management,

Naamsestraat 69, B-3000 Leuven, Belgium,

Abstract
In this paper we will investigate how to sequence surgical cases in a day-care facility so that multiple objectives are simultaneously optimized. The limited availability of resources and the occurrence of medical precautions, such as an additional cleaning of the operating room after the surgery of an infected patient, are taken into account. A branch-and-price methodology will be introduced in order to develop both exact and heuristic algorithms. In this methodology, column generation is used to optimize the linear programming formulation of the scheduling problem. Both a dynamic programming approach and an integer programming approach will be specified in order to solve the pricing problem. The column generation procedure will be combined with various branching schemes in order to guarantee the integrality of the solutions. The resulting solution procedures will be thoroughly tested and evaluated using real-life data of the surgical day-care center at the university hospital Gasthuisberg in Leuven (Belgium). Computational results will be summarized and conclusions will eventually be formulated.

Keywords: Branch-and-price; Column generation; Health care operations; Scheduling.

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Key words: Customer lifetime value; Value; Yield; Companies; Order; Model; Product; Expected

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 22:17:00 +0700

Boute R, Lambrecht MR, Lambrechts O and Sterckx P

Abstract: Various inventory studies have been published in the last decades. Some studies emphasize the importance of low inventories, other examine the evolution of inventories over time and especially focus on the impact of the just-in-time (JIT) revolution. The aim of this paper is to investigate the level of inventories held by Belgian companies at one moment in time, namely May 2004. First we examine differences in inventory ratios between manufacturing industry sectors as well as between wholesale and retail. We find empirical evidence that the type of production process is the most important driver for work in process inventory. The finished goods inventory ratio also differs significantly among industry sectors, but here the reasons for the difference are harder to distinguish. Finally we find the inventory ratio to be significantly higher in retail than in wholesale. Furthermore, we examine the financial impact of inventories in the manufacturing industry. We find that companies with very high inventory ratios have more chance to be bad financial performers. Regression analyses partially support the hypothesis of a negative relationship between inventory ratio and financial performance but significant results could not be obtained for all sectors.

Key words: Inventory; Manufacturing

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A Modified Pareto/NBD Approach for Predicting Customer

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 22:01:00 +0700

Nicolas Glady, Bart Baesens and Christophe Croux

Faculty of Economics and Management, K.U.Leuven

School of Management, University of Southampton

Abstract
Valuing customers is a central issue for any commercial activity. The customer lifetime value (CLV) is the discounted value of the future profits that this customer yields to the company. In order to compute the CLV, one needs to predict the future number of transactions a customer will make and the pro¯t of these transactions. With the Pareto/NBD model, the future number of transactions of a customer can be predicted, and the CLV is then computed as a discounted product between this number and the expected profit per transaction. Usually, the number of transactions and the future profits per transaction are estimated separately. This study proposes an alternative. We show that the dependence between the number of transactions and
their probability can be used to increase the accuracy of the prediction of the CLV. This is illustrated with a new empirical case from the retail banking sector.

Keywords: Customer lifetime value; Value; Yield; Companies; Order; Model; Product; Expected.

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Sums and Products of Jointly Distributed Random Variables: A Simplified Approach

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:53:00 +0700

Sheldon H. Stein

Cleveland State University
Journal of Statistics Education Volume 13, Number 3 (2005),

Abstract

Three basic theorems concerning expected values and variances of sums and products of random variables play an important role in mathematical statistics and its applications in education, business, the social sciences, and the natural sciences. A solid understanding of these theorems requires that students be familiar with the proofs of these theorems. But while students who major in mathematics and other technical fields should have no difficulties coping with these proofs, students who major in education, business, and the social sciences often find it difficult to follow these proofs. In many textbooks and courses in statistics which are geared to the latter group, mathematical proofs are sometimes omitted because students find the mathematics too confusing. In this paper, we present a simpler approach to these proofs. This paper will be useful for those who teach students whose level of mathematical maturity does not include a solid grasp of differential calculus.

Keywords: Covariance; Joint probability distribution; Means; Variances.

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Characteristics and Performance of Students in an Online Section of Business Statistics

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:50:00 +0700

John Dutton

North Carolina State University

Marilyn Dutton

North Carolina Central University
Journal of Statistics Education Volume 13, Number 3 (2005),

Abstract

We compare students in online and lecture sections of a business statistics class taught simultaneously by the same instructor using the same content, assignments, and exams in the fall of 2001. Student data are based on class grades, registration records, and two surveys. The surveys asked for information on preparedness, reasons for section choice, and evaluations of course experience and satisfaction. Using descriptive statistics, regression analysis and standard hypothesis tests, we test for significant differences between the online and lecture sections with regard to performance and satisfaction with the course as well as motivation and preparedness for taking an online course. We report several differences, including better performance by online students.

Keywords: Distance education; Internet course; Online education.

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Demonstration of Ranking Issues for Students: A Case Study

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:48:00 +0700

I. Elaine Allen

Babson College

Norean Radke Sharpe

Babson College
Journal of Statistics Education Volume 13, Number 3 (2005),

Abstract

This article uses a case study of 2001 town and city data that we analyzed for Boston Magazine. We use this case study to demonstrate the challenges of creating a valid ranking structure. The data consist of three composite indices for 147 individual townships in the Boston metropolitan area representing measures of public safety; the environment; and health. We report the data and the basic ranking procedure used in the magazine article, as well as a discussion of alternative ranking procedures. In particular, we demonstrate the impact of additional adjustment for the size of population, even when per capita data are used. This case study presents an opportunity for discussion of fundamental data analysis concepts in all levels of statistics courses.

Keywords: Data Analysis; Demographics; Graphics; Rank methods.

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Building the Numeracy Skills of Undergraduate and Elementary School Students

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:46:00 +0700

Pam Boger

Ohio University
Journal of Statistics Education Volume 13, Number 3 (2005),

Abstract

This paper describes a project with the goal of exposing both elementary school and undergraduate students to the concepts associated with the experimental method, from the formulation of a researchable question to the analysis and interpretation of the results. Under the guidance of their university mentors, fourth and fifth grade students formulated a research question, designed an experiment to answer that inquiry, recorded the appropriate measurements, calculated the necessary statistics, created visual displays of their results, and interpreted their findings at a student-centered Numeracy Conference.

Keywords: Active learning; Elementary statistics education, Numeracy.

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4 out of 5 Students Surveyed Would Recommend this Activity (Comparing Chewing Gum Flavor Durations)

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:37:00 +0700

Mary Richardson

Grand Valley State University

Neal Rogness

Grand Valley State University

Byron Gajewski

The University of Kansas Medical Center
Journal of Statistics Education Volume 13, Number 3 (2005),

Abstract

This paper describes an interactive activity developed for illustrating hypothesis tests on the mean for paired or matched samples. The activity is extended to illustrate assessing normality, the Wilcoxon signed rank test, Kaplan-Meier survival functions, two-way analysis of variance, and the randomized block design.

Keywords: Active learning; Assessing normality; Blinding; Confounding variable; Kaplan-Meier survival function; Paired difference experiment; Randomization; Randomized block design; Right-censored data; Two-way analysis of variance; Wilcoxon signed rank test.

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Teaching an Introductory Statistics Course with CyberStats, an Electronic Textbook

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:34:00 +0700

Jürgen Symanzik and Natascha Vukasinovic

Utah State University
Journal of Statistics Education Volume 14, Number 1 (2006),

Abstract

In the Fall 2001 semester, we taught a “Web-enhanced” version of the undergraduate course “Statistical Methods” (STAT 2000) at Utah State University. The course used the electronic textbook CyberStats in addition to “face-to-face” teaching. This paper gives insight in our experiences in teaching this course. We describe the main features of CyberStats, the course content and the teaching techniques used in class, students' reactions and performance, and some specific problems encountered during the course. We compare this Web-enhanced course with other similar textbook-based courses and report instructors' and students' opinions. We finish with a general discussion of advantages and disadvantages of a Web-enhanced statistics course.

Keywords: Key Words: Computer; Interactivity; Statistical Concepts; Undergraduate Course; Web-enhanced Course.

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Advice for New and Student Lecturers on Probability and Statistics

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:28:00 +0700

Michael D. Larsen

Iowa State University
Journal of Statistics Education Volume 14, Number 1 (2006),

Abstract

Lecture is a common presentation style that gives instructors a lot of control over topics and time allocation, but can limit active student participation and learning. This article presents some ideas to increase the level of student involvement in lecture. The examples and suggestions are based on the author’s experience as a senior lecturer for four years observing and mentoring graduate student instructors. The ideas can be used to modify or augment current plans and preparations to increase student participation. The ideas and examples will be useful as enhancements to current efforts to teach probability and statistics. Most suggestions will not take much class time and can be integrated smoothly into current preparations.

Keywords: Active learning; Contrasts; Problem Solving; Statistical Reasoning; Student Participation; Teaching Methods.

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There Once Was a 9-Block ...- A Middle-School Design for Probability and Statistics

callfarid@gmail.com (Hafiz's FATHER) — Wed, 11 Jun 2008 21:24:00 +0700

Dor Abrahamson

University of California, Berkeley

Ruth M. Janusz

Nichols Middle School, Evanston, IL

Uri Wilensky

Northwestern University

Journal of Statistics Education Volume 14, Number 1 (2006),

Abstract

ProbLab is a probability-and-statistics unit developed at the Center for Connected Learning and Computer-Based Modeling, Northwestern University. Students analyze the combinatorial space of the 9-block, a 3-by-3 grid of squares, in which each square can be either green or blue. All 512 possible 9-blocks are constructed and assembled in a “bar chart” poster according to the number of green squares in each, resulting in a narrow and very tall display. This combinations tower is the same shape as the normal distribution received when 9-blocks are generated randomly in computer-based simulated probability experiments. The resemblance between the display and the distribution is key to student insight into relations between theoretical and empirical probability and between determinism and randomness. The 9-block also functions as a sampling format in a computer-based statistics activity, where students sample from a “population” of squares and then input and pool their guesses as to the greenness of the population. We report on an implementation of the design in two Grade 6 classrooms, focusing on student inventions and learning as well as emergent classroom socio-mathematical behaviors in the combinations-tower activity. We propose an application of the 9-block framework that affords insight into the Central Limit Theorem in science.

Keywords: Computers; Education; Mathematics; Sample; Statistics.

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Plan and Operation of the NHANES II Mortality Study

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:58:00 +0700

Abstract

Objectives
The NHANES II Mortality Study is a prospective study of adult participants examined in the second National Health and Nutrition Examination Survey (NHANES II) conducted between 1976 and 1980. It was designed to investigate the association between factors measured at baseline and mortality. The methods used in the study are described and assessed in this report.

Methods
The vital status of NHANES II participants who were 30–75 years of age at their examination was ascertained after 12–16 years. Vital status was assessed by searching the National Death Index and the Social Security Administration Death Master File for deaths occurring in the United States. Causes of death were obtained from the National Center for Health Statistics Multiple Cause of Death file or death certificates. To assess how well mortality was ascertained, the survival of the cohort after 5 and 10 years was compared to that of the U.S. population during the same period.

Results
As of December 31, 1992, 23.2 percent of the 9,250 cohort members were found to be deceased.
The remaining 76.8 percent that were not found to be deceased may be assumed to be alive for analytic purposes. Cumulative survival probabilities for the cohort were generally higher than probabilities calculated from U.S. life table data. Although some differences were expected, these data suggest that after 10 years of follow-up using passive methods, mortality may have been under ascertained for the cohort. Discrepancies between the survival patterns for NHANES II cohort and U.S. vital statistics were larger for black than for white participants, indicating that ascertainment of mortality was poorer among black participants. Researchers using the NHANES II Mortality Study, 1992 data should be aware of these study limitations.

Keywords: Epidemiologic methods, data collection c health surveys, cohort studies, longitudinal study, follow-up studies.

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Plan and Operation of Cycle 6 of the National Survey of Family Growth

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:53:00 +0700

Abstract

Objectives
This report describes how Cycle 6 of the National Survey of Family Growth (NSFG) was designed, planned, and implemented. The NSFG is a national survey of women and men 15–44 years of age designed to provide national estimates of factors affecting pregnancy and birth rates; men’s and women’s health; and parenting. Cycle 6, conducted in 2002, was the first time the NSFG included a sample of males.

Methods
The survey used in-person, face-to-face interviews conducted by trained female interviewers. One person per household was interviewed from a national area probability sample in about 120 sample areas, with oversamples of teenagers, African Americans, and Hispanics. The data collection used computer-assisted personal interviewing (CAPI). Separate questionnaires were used for female and male respondents. The last section of the questionnaires used a technique called audio computer-assisted self-interviewing (ACASI). In order to control costs and nonresponse errors, survey managers statistically analyzed results from interviewers’ visits to sampled households each day, and used those results to allocate interviewer labor and other resources more efficiently. This management improved response rates and made the sample more representative.

Results
Over 12,500 interviews were completed, about 7,600 with females and about 4,900 with males. The response rate was about 80 percent for females and about 78 percent for males. The survey procedures were adapted during the fieldwork to achieve the desired response rates and to control costs.

Keywords: Computer-assisted personal interviewing (CAPI) c survey methodology c response rates c audio computer-assisted self-interviewing (ACASI) c eligibility rate c National Survey of Family Growth .

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Teaching Introductory Statistics Online – Satisfying the Students

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:46:00 +0700

Gail E. Tudor

Husson College

Abstract

This paper describes the components of a successful, online, introductory statistics course and shares students’ comments and evaluations of each component. Past studies have shown that quality interaction with the professor is lacking in many online courses. While students want a course that is well organized and easy to follow, they also want to interact with the professor and other students. Interactions in this course took place through small group discussions, emails, weekly announcements and graded exams. The course also contained lecture slides with audio prepared by the professor. As the variety and quantity of interaction increased, student satisfaction with the amount of interaction with the professor increased from 75% the first year of the course to 99% the fifth year. Overall satisfaction with the online course increased from 93% the first year to 100% the fifth year.

Keywords: Course design; Online versus traditional learning; Statistics education.

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Attitudes Toward Statistics and Their Relationship with Short- and Long-Term Exam Results

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:41:00 +0700

Stijn Vanhoof

Ana Elisa Castro Sotos

Patrick Onghena

Lieven Verschaffel

Wim Van Dooren

Wim Van den Noortgate

Katholieke Universiteit Leuven
Journal of Statistics Education Volume 14, Number 3 (2006),

Abstract

This study uses the Attitudes Toward Statistics (ATS) scale (Wise 1985) to investigate the attitudes toward statistics and the relationship of those attitudes with short- and long-term statistics exam results for university students taking statistics courses in a five year Educational Sciences curriculum. Compared to the findings from previous studies, the results indicate that the sample of undergraduate students have relatively negative attitudes toward the use of statistics in their field of study but relatively positive attitudes toward the course of statistics in which they are enrolled. Similar to other studies, we find a relationship between the attitudes toward the course and the results on the first year statistics exam. Additionally, we investigate the relationship between the attitudes and the long-term exam results. A positive relationship is found between students’ attitudes toward the use of statistics in their field of study and the dissertation grade. This relationship does not differ systematically from the one between the first year statistics exam results and the dissertation grade in the fifth year. Thus, the affective and cognitive measures at the beginning of the curriculum are equally predictive for long-term exam results. Finally, this study reveals that the relationship between attitudes toward statistics and exam results is content-specific: We do not find a relationship between attitudes and general exam results, only between attitudes and results on statistics exams.

Keywords: Assessment; Attitudes Toward Statistics scale.

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Classroom Research: Assessment of Student Understanding of Sampling Distributions of Means and the Central Limit Theorem in Post-Calculus Probability

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:37:00 +0700

M. Leigh Lunsford - Longwood University
Ginger Holmes Rowell - Middle Tennessee State University
Tracy Goodson-Espy - Appalachian State University

Abstract

We applied a classroom research model to investigate student understanding of sampling distributions of sample means and the Central Limit Theorem in post-calculus introductory probability and statistics courses. Using a quantitative assessment tool developed by previous researchers and a qualitative assessment tool developed by the authors, we embarked on data exploration of our students’ responses on these assessments. We observed various trends regarding their understanding of the concepts including results that were consistent with research completed previously (by other authors) for algebra-based introductory level statistics students. We also used the information obtained from our data exploration and our experiences in the classroom to examine and conjecture about possible reasons for our results.

Keywords: Action Research.

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An Active Tutorial on Distance Sampling

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:35:00 +0700

Alice Richardson - University of Canberra

Abstract

The technique of distance sampling is widely used to monitor biological populations. This paper documents an in-class activity to introduce students to the concepts and the mechanics of distance sampling in a simple situation that is relevant to their own experiences. Preparation details are described. Variations and extensions to the activity are also suggested.

Keywords: Estimation; Proportions; Sampling distribution; Statistical education.

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Probability in Action: the Red Traffic Light

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:30:00 +0700

John A. Shanks University of Otago
Journal of Statistics Education Volume 15, Number 1 (2007),

Abstract

Emphasis on problem solving in mathematics has gained considerable attention in recent years. While statistics teaching has always been problem driven, the same cannot be said for the teaching of probability where discrete examples involving coins and playing cards are often the norm. This article describes an application of simple probability distributions to a practical problem involving a car’s approach to a red traffic light, and draws on the ideas of density functions, expected value and conditional distributions. It provides a valuable exercise in applying theory in a practical context.

Keywords: Distributions; Modelling; Optimization; Problem solving.

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A Bubble Mixture Experiment Project for Use in an Advanced Design of Experiments Class

callfarid@gmail.com (Hafiz's FATHER) — Thu, 5 Jun 2008 22:19:00 +0700

Stefan H. Steiner - University of Waterloo
Michael Hamada - Los Alamos National Laboratory
Bethany J. Giddings White - University of Waterloo
Vadim Kutsyy - Guardian Analytics
Sofia Mosesova - University of Waterloo
Geoffrey Salloum - Camosun College

Journal of Statistics Education Volume 15, Number 1 (2007)

Abstract

This article gives an example of how student-conducted experiments can enhance a course in the design of experiments. We focus on a project whose aim is to find a good mixture of water, soap and glycerin for making soap bubbles. This project is relatively straightforward to implement and understand. At its most basic level the project introduces students to mixture experiments and general issues in experimental design such as choosing and measuring an appropriate response, selecting a design, the effect of using repeats versus replicates, model building, making predictions, etc. To accommodate more advanced students, the project can be easily enhanced to draw on various areas of statistics, such as generalized linear models, robust design, and optimal design. Therefore it is ideal for a graduate level course as it encourages students to look beyond the basics presented in class.

Keywords: Constrained experimental region; Generalized linear model; Optimal design; Poisson regression; Robust parameter design.

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