• Title/Summary/Keyword: Shapiro-Wilk Test

Search Result 82, Processing Time 0.029 seconds

Test of Normality Based on the Transformed Lorenz Curve

  • Kang, Suk-Bok;Cho, Young-Suk
    • Communications for Statistical Applications and Methods
    • /
    • v.6 no.3
    • /
    • pp.901-908
    • /
    • 1999
  • Using the Transformed Lorenz curve which is introduced by Cho et al.(1999) we propose the test statistic for testing of normality that is very important test in statistical analysis and compare the proposed test statistic with the Shapiro and Wilk's W test statistic in terms of the power of test through by Monte Carlo method.

  • PDF

A Study on the Effects of Ethical Dilemma Discussion Program for University Students (대학생의 윤리적 딜레마 토의 프로그램 효과에 관한 연구)

  • Yang, Hyun-Joo;Park, Mee-Ra;Je, Nam-Joo
    • Journal of Digital Convergence
    • /
    • v.17 no.9
    • /
    • pp.291-299
    • /
    • 2019
  • This study is a nonequivalent control group pretest-posttest designed to understand the effect of ethical dilemma discussion program on human rights sensitivity and ethical values of university students. By providing ethical dilemma discussion program to university students in C university, G-do, the effectiveness was verified. Analyzed using IBM SPSS 24.0. The normality of the variables was verified by Shapiro-Wilk test. Homogeneity was verified using real number and percentage, Fisher's exact probability test and independent t-test. The program's effect was verified using paired t-test. The results of this study are as follows: after the ethical dilemma discussion program, the experimental group's human rights sensitivity(t=-2.32, p=.025), and ethical value(t=-2.43, p=.020) were higher than the control group. Therefore, the ethical dilemma discussion program of this study helped improve the human rights susceptibility and ethical values of the subjects. Further research is needed to verify the effects of ethics education on diverse groups.

A Study on Accuracy of Meteorological Information for Low Altitude Aerospace around the Airport on the West Coast (서해안 인접공항의 저고도 항공기상 정확도 연구)

  • Cho, Young-Jin;Yoo, Kwang Eui
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.28 no.2
    • /
    • pp.53-62
    • /
    • 2020
  • This study is to evaluate the accuracy of the meteorological information provided for the aircraft operating at low altitude. At first, it is necessary to identify crucial elements of weather information closely related to flight safety during low altitude flights. The study conducted a survey of pilots of low altitude aircraft, divided into pre-flight and in-flight phases, and reached an opinion that wind direction, wind speed, cloud coverage and ceiling and visibility are important items. Related to these items, we compared and calculated the accuracy of TAFs and METARs from Taean Airfield, Seosan Airport and Gunsan Airport because of their high number of domestic low-altitude flights. Accuracy analysis evaluated the accuracy of two numerical variables, Mean Absolute Error(MAE) and Root Mean Square Error(RMSE), and the cloud coverage which is categorical variable was calculated and compared by accuracy. For numeric variables, one-way ANOVA, which is a parameter-test, was approached to identify differences between actual forecast values and observations based on absolute errors for each item derived from the results of MAE and RMSE accuracy analyses. To determine the satisfaction of both normality assumptions and equivalence variability assumptions, the Shapiro-Wilk test was performed to verify that they do not have a normality distribution for numerical variables, and for the non-parametric test, Kruscal-Wallis test was conducted to determine whether or not they are satisfied.

Effect of chest compressions on the quality of back pain prevention and chest compressions by applying body stabilization Convergence movement (체간안정화 융합운동을 접목한 가슴압박이 요통예방과 가슴압박 품질에 미치는 영향)

  • Hong, Eun-Jeong;Cho, Byung-Jun;Kim, Gyoung-Young
    • Journal of the Korea Convergence Society
    • /
    • v.10 no.5
    • /
    • pp.85-94
    • /
    • 2019
  • This study was aimed to identify a study on the effect of chest compressions combined with abdominal drawing-in technique on prevention of back pain and chest compression quality. We tested motion analysis, electromyography, and chest compression quality of 15 paramedics. Data were normalized to SPSS 21.0 (Kolmogorov-Smirnov and Shapiro-Wilk test). The paired t-test was used for the pre- and post-test chest compressions, the one-way ANOVA was used for the analysis of the measurement point-in-time differences, and LSD was used for the post-test. The results of the study showed significant difference in muscle activity and chest compression success rate when the chest pressure was applied with abdomen drawing-in. Therefore, it is necessary to study cardiopulmonary resuscitation education which can increase the chest compression success rate while preventing the back pain of the paramedics in the future.

Testing Log Normality for Randomly Censored Data (임의중도절단자료에 대한 로그정규성 검정)

  • Kim, Nam-Hyun
    • The Korean Journal of Applied Statistics
    • /
    • v.24 no.5
    • /
    • pp.883-891
    • /
    • 2011
  • For survival data we sometimes want to test a log normality hypothesis that can be changed into normality by transforming the survival data. Hence the Shapiro-Wilk type statistic for normality is generalized to randomly censored data based on the Kaplan-Meier product limit estimate of the distribution function. Koziol and Green (1976) derived Cram$\acute{e}$r-von Mises statistic's randomly censored version under the simpl hypothesis. These two test statistics are compared through a simulation study. As for the distribution of censoring variables, we consider Koziol and Green (1976)'s model and other similar models. Through the simulation results, we can see that the power of the proposed statistic is higher than that of Koziol-Green statistic and that the proportion of the censored observations (rather than the distribution of censoring variables) has a strong influence on the power of the proposed statistic.

The Effects of Human Relations and Communication Education on Nursing Students (간호대학생의 인간관계와 커뮤니케이션 교육의 효과)

  • Choi, HeeJung
    • The Journal of the Convergence on Culture Technology
    • /
    • v.8 no.1
    • /
    • pp.253-260
    • /
    • 2022
  • The purpose of this study was to identify the effects of human relations and communication education on nursing students. The participants were 82, 1 grad of students of U university in G city. The data were collected from September 3 to December 6, 2019, and analyzed using the SPSS/WIN 21.0 program with descriptive statistics, Shapiro-Wilk, Paired t-test. There were statistically significant differences in the subject's communication skill(t=-2.87, p=.005), communicative competence self-appraisal(t=-3.80, p=<.001) before and after human relations and communication education, but there was no statistically significant difference between interpersonal communication(t=-0.09, p=.931) and human relationship(t=-0.83, p=.409). Communication skills and skills are important nursing areas for nursing students as well as practical nurses, so continuous communication education is required. Therefore, it is necessary to develop a step-by-step program for improving communication skills of nursing students, apply continuous and repetitive education in connection from the lower grades to the upper grades, and follow-up research to verify the effect.

Comprehensive comparison of normality tests: Empirical study using many different types of data

  • Lee, Chanmi;Park, Suhwi;Jeong, Jaesik
    • Journal of the Korean Data and Information Science Society
    • /
    • v.27 no.5
    • /
    • pp.1399-1412
    • /
    • 2016
  • We compare many normality tests consisting of different sources of information extracted from the given data: Anderson-Darling test, Kolmogorov-Smirnov test, Cramervon Mises test, Shapiro-Wilk test, Shaprio-Francia test, Lilliefors, Jarque-Bera test, D'Agostino' D, Doornik-Hansen test, Energy test and Martinzez-Iglewicz test. For the purpose of comparison, those tests are applied to the various types of data generated from skewed distribution, unsymmetric distribution, and distribution with different length of support. We then summarize comparison results in terms of two things: type I error control and power. The selection of the best test depends on the shape of the distribution of the data, implying that there is no test which is the most powerful for all distributions.

A Modification of the W Test for Exponentiality

  • Kim, Nam-Hyun
    • Communications for Statistical Applications and Methods
    • /
    • v.8 no.1
    • /
    • pp.159-171
    • /
    • 2001
  • Shapiro and Wilk (1972) developed a test for exponentiality with origin and scale unknown. The procedure consists of comparing the generalized least squares estimate of scale with the estimate of scale given by the sample variance. However the test statistic is inconsistent ; that is, the power of the test will not approach 1 as the sample size increases. Hence we give a test based on the ratio of two asymptotically efficient estimates of scale. We also have conducted a power study to compare the test procedures, using Monte Carlo samples from a wide range of alternatives. It is found that the suggested statistics have higher power for the alternatives with the coefficient of variation greater that or equal to 1.

  • PDF

Statistical evaluation of the monotonic models for FRP confined concrete prisms

  • Hosseinpour, Farid;Abdelnaby, Adel E.
    • Advances in concrete construction
    • /
    • v.3 no.3
    • /
    • pp.161-185
    • /
    • 2015
  • FRP confining is a widely used method for seismic retrofitting of concrete columns. Several studies investigated the stress-strain behavior of FRP confined concrete prisms with square and rectangular sections both experimentally and analytically. In some studies, the monotonic stress-strain behavior of confined concrete was investigated and compressive strength models were developed. To study the reliability of these models, thorough statistical tests are required. This paper aims to investigate the reliability of the presented models using statistical tests including t-test, wilcoxon rank sum test, wilcoxon signed rank test and sign test with a level of significance of 5%. Wilk Shapiro test was also employed to evaluate the normality of the data distribution. The results were compared for different cross section and confinement types. To see the accuracy of the models when there were no significant differences between the results, the coefficient of confidence was used.

The Effect of Abdominal Massage on Sleep Colonoscopy Subjects (수면 대장내시경 검진자에게 시행한 복부마사지의 효과)

  • Lee, Yun-Jeong;Je, Nam-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.6
    • /
    • pp.410-420
    • /
    • 2019
  • The purpose of this study is to investigate the effect of abdominal massage, on abdominal bloating and the recovery of bowel movement after sleep colonoscopy. The study design is the time difference before and after the non-equality control. The subjects were 22 patients each in experimental group and control group who recieved sleep colonoscopy at the G hospital in C city, The data collection period was from June 1, 2018 to August 25, 2018, and the control group's data were first collected with time difference from the collection of experimental group's data to prevent the spread of the experiment. Data were analyzed using IBM SPSS 24.0 and tested by independent sample t-test, $x^2-test$ and Fisher's exact probability test to verify the homogeneity of general characteristics of the subjects. Shapiro-Wilk was used to verify the normality of the abdominal circumference changes in the experimental and control groups. Mann-Whitney U test was used to verify the pre-homogeneity of the abdominal circumference of the subjects. The experimental results were verified by Fisher's exact probability test, Friedman test and Mann-Whitney U test. These results suggest that the abdominal massage can be used as a nursing intervention after sleep colonoscopy by reducing the gas discharge time($x^2=19.75$, p<.001) and abdominal bloating($x^2=29.93$, p<.001).