• Journal of the Korean School Mathematics Society
• /
• v.23 no.3
• /
• pp.259-276
• /
• 2020

The purpose of this study was to identify how didactic transposition (teaching and learning methods) has occurred and developed in the teaching of graphs in elementary school mathematics textbooks for third and fourth graders according to the previous and current curricula. In this study, we analyzed the lesson units on bar graphs and line graphs in mathematics textbooks for each curriculum, from the fifth curriculum to the 2015 revised curriculum. We also investigated the implication of statistics education deriving from didactic transposition (teaching and learning methods). We found that the timing of teaching bar and line graphs was rarely changed as the curriculum has changed. In addition, the use of technology was not actively implemented in school statistics, although the curriculum emphasized the use of technology in statistical education. Lastly, the textbooks did not address the variability and distribution of data and the sample or sampling process, which are significant statistical concepts. Based on the findings of this study, we suggest how to teach statistical graphs and what to consider for the next mathematics textbook.

• Communications for Statistical Applications and Methods
• /
• v.16 no.1
• /
• pp.185-193
• /
• 2009

Machine learning methods such as support vector machines and random forests yield nonparametric prediction functions of the form y = $f(x_1,{\ldots},x_p)$. As a sequel to the previous article (Huh and Lee, 2008) for visualizing nonparametric functions, I propose more sensible graphs for visualizing y = $f(x_1,{\ldots},x_p)$ herein which has two clear advantages over the previous simple graphs. New graphs will show a small number of prototype curves of $f(x_1,{\ldots},x_{j-1},x_j,x_{j+1}{\ldots},x_p)$, revealing statistically plausible portion over the interval of $x_j$ which changes with ($x_1,{\ldots},x_{j-1},x_{j+1},{\ldots},x_p$). To complement the visual display, matching importance measures for each of p predictor variables are produced. The proposed graphs and importance measures are validated in simulated settings and demonstrated for an environmental study.

• Communications for Statistical Applications and Methods
• /
• v.10 no.3
• /
• pp.695-705
• /
• 2003

In this article, we propose a regression and correlation analysis via dynamic graphs and implement them in Java Web Start. For the polynomial relations between dependent and independent variables, dynamic graphics are implemented for both polynomial regression and spline estimates for an instant model selection. The results include basic statistics. They are available both as a web-based service and an application.

• Communications for Statistical Applications and Methods
• /
• v.15 no.3
• /
• pp.343-351
• /
• 2008

By supervised learning with p predictors, we frequently obtain a prediction function of the form $y\;=\;f(x_1,...,x_p)$. When $p\;{\geq}\;3$, it is not easy to understand the inner structure of f, except for the case the function is formulated as additive. In this study, we propose to use p simple graphs for visual understanding of complex prediction functions produced by several supervised learning engines such as LOESS, neural networks, support vector machines and random forests.

• Journal of Elementary Mathematics Education in Korea
• /
• v.7 no.1
• /
• pp.65-86
• /
• 2003

Mathematics textbooks are substitutive showing real characters of didactic transposition in pseudo-contextualization and pseudo-personalization. This study analyzed statistical graphs in elementary school mathematics textbooks according to the first to the 7th curriculum in Korea. It focused on the didactic principles used in those methods through those view of Didactic Transposition Theory. The features of the elementary school mathematics textbooks in Korea are investigated and described ethnomethodologically according to each curriculum periods in dividing bar graph, line graph, pictograph, graph of ratio, histogram. The teaching sequences and methods of the statistical graphs, order and methods of sub-learning activities, teaming data, matter of the learning activity indicator were summarized. Usually, the teaching sequences, excepting the graphs of ratio, statistical graphs are introduced in the second semester of each grade. The graph of ratio is introduced in the first semester of 6th grade. As a result of analysing sub-Loaming activities, using them increased from the first to the 7th curriculum and its form was fixed constructive and stable at the 4th curriculum textbooks. As a result of analysing the teaming data, the data of the social aspects are used more frequently and the data of the individual preferences trended more gradually. As a result of analysing the matter of the teaming activity indicators, concept-explanation question style were used more frequently. Statement-practice style and consideration style trended gradually. Concluding remarks are: First, the didactic transposition of the elementary school mathematics textbooks developed systematically according to the first to the 7th curriculum; Second, mathematics textbooks gradually introduced the positive learning style of activity and the learners' spontaneousness; Third, more concrete practice activities and reflective activities were variously introduced considering the level and interest of each elementary student.

• Journal of the military operations research society of Korea
• /
• v.29 no.2
• /
• pp.13-25
• /
• 2003

The lack of consideration for statistical properties in Taguchi's three­level linear graphs is rectified. We propose a new set of linear graphs for the three­level orthogonal arrays according to the maximum resolution criterion. In the presence of two­factor interactions however, the serious bias of all the estimated effects as well as the estimated variance shows that these designs should not be employed. The various alternative designs are discussed.

• Journal of Information Technology Applications and Management
• /
• v.22 no.3
• /
• pp.65-81
• /
• 2015

This study reports a preliminary finding of the types and numbers of graphs being presented in the annual reports of about thirty top listed companies trading publicly in the stock markets of three countries-Thailand (SET), Malaysia (BM), and Singapore (SGX)-that were chosen based on their inclusion in the ASEAN Stars Index under the ASEAN Trading Link project. A total of 6,753 graphs from nineteen sectors were extracted and examined. Banking, real estate, and telecommunications are ranked the three most condense sectors, accounting for 50.2% of the total number of graphs observed. The three most used graphs are the Conservative Bar, Donut graph and Stack Bar. Less than one percent of Infographic type graphs were used. The five most depicted graphed variables are Asset, Revenue, Net profit, Liability, and Dividend. Using rudimentary framework to detect distorted or misleading statistical graphs, the study found 60.6% of the graphs distorted across the three markets, SET, BM, and SGX. BM ranked first in percentages of graphs being distortedly presented (73%). The other two markets, SET and SGX, have about the same proportions, 53.88% and 53.03%, respectively. Likewise, the proportions of Well-designed versus Inappropriate-designed graphs of the latter two markets are a little over one time (SET = 1 : 1.17; SGX = 1 : 1.13), whereas the proportion is almost triple for the BM market (BM = 1 : 2.70). In addition, the trend of distorted graphs found is slightly increasing as the longevity of the ASEAN Stars Index increases. One possible explanation for the relatively equal proportion of inappropriate graphs found is that SET is the smallest market and SGX, though the largest, is the most regulated market. BM, on the other hand, may want to present their financial data in the most attractive manner to prospective investors, thus, regulatory constraints and governance structure are still lenient.

• Communications for Statistical Applications and Methods
• /
• v.12 no.2
• /
• pp.425-433
• /
• 2005

Most of national-wide surveys are summarized by some statistical tables and graphs. In spite of high costs to get statistical results from surveys, we often find some statistical problems in the statistical reports. In this paper, we point out some statistical problems for the Korean Anthropometric Survey report. Also, we suggest some alternatives which may avoid the illustrated problems.

• Communications for Statistical Applications and Methods
• /
• v.6 no.3
• /
• pp.821-830
• /
• 1999

In This paper we calculate the probabilities of binomial and Poisson distributions when n or${\mu}$ is large. Based on this calculation we consider the normal approximation to the binomial and binomial approximation to Poisson. We implement this approximation via CGI and dynamic graphs. These implementation are made available through the internet.

• The Korean Journal of Applied Statistics
• /
• v.15 no.2
• /
• pp.433-448
• /
• 2002

Revelation is emphasized in exploratory data analysis. Hence, many graphical techniques are used in exploratory data analysis. Three applications of graphs in exploratory data analysis are presented.