• Title, Summary, Keyword: F-test

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A Study on Test for New Better than Used of an unknown specified age ($NBU-t_0$ Class에 대한 검정법 연구)

  • 김환중
    • Journal of the Korean Society for Quality Management
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    • v.29 no.2
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    • pp.37-45
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    • 2001
  • A survival variable is a non-negative random variable X with distribution function F(t) satisfying F(0) : 0 and a survival function F(t): 1-F(t). This variable is said to be New Better than Used of specified age t$_{0}$ if F(x+ t$_{0}$)$\leq$F(x).F(t$_{0}$) for all x$\geq$0 and a fixed t$_{0}$. We propose the test for H$_{0}$ : F(x+t$_{0}$)=F(x).F(t$_{0}$) for all x$\geq$0 against H$_1$: F(x+t$_{0}$) $\leq$ F(x).F(t$_{0}$) for all x$\geq$0 when the specified age to is unknown but can be estimated from the data when t$_{0}$$_{p}$, the pth percentile of F. This test statistic, which is based on the normalized spacings between the ordered observations, is readily applied in the case of small sample. Also, our test is more simple than Ahmad's test (1998). Finally, the performance of our test is presented.our test is presented.

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The Reliability and Validity of Figure-of-8 Walk Test in Patients with Stroke (뇌졸중 환자에서 Figure-of-8 walk test의 신뢰도와 타당도)

  • Kim, Yang-Ho;Lim, Jae-Heon
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.10 no.1
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    • pp.29-37
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    • 2012
  • Purpose : The purpose of this study was to establish intra-rater, inter-rater, test-retest reliability, and concurrent validity of figure-of-8 walk test in people with stroke. Methods : The subjects of this study were 17 patients who were diagnosed with a stroke. Subjects were tested twice by the same raters, with 1 day between tests. Subjects were assessed by two physical therapists. Test-retest reliability was calculated using intraclass correlation coefficients (ICC). The concurrent validity was demonstrated by spearman correlation of F8WT with 10m walking test (10MWT), timed up and go test (TUG), Berg balance scale (BBS), dynamic gait index (DGI) and four square step test (FSST). Results : Intra-rater, inter-rater, test- retest of F8WT time, showed high reliability. Intra-rater, inter-rater, test-retest of F8WT steps demonstrated high reliability. Intra-rater, inter-rater, test-retest of F8WT total smoothness score showed below moderate reliability. There was a significant positive correlation of F8WT time with 10MWT, TUG, FSST. There was a significant negative correlation of F8WT time with DGI, BBS. There was a significant positive correlation of F8WT steps with 10MWT, TUG, FSST. There was a significant negative correlation of F8WT steps with DGI. There was a significant positive correlation of F8WT test total smoothness score with BBS. Conclusion : The time, and number of steps in F8WT show high inter, intra-rater, test-retest reliability. The F8WT smoothness shows below moderate reliability. The F8WT shows high concurrent validity with other comparable balance, and walking tests. The F8WT is a valid and reliable measure for assessing walking function in patients with a stroke.

Type I Error Rates and Power for Omnibus Tests of Repeated Measures Measn in the Split-Plot Design : F test, $\widetilde{\xi}$F test, and CIGA test

  • Kim, Hyunchul
    • Communications for Statistical Applications and Methods
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    • v.4 no.1
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    • pp.139-149
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    • 1997
  • For split plot designs exact univariate F tests of the within-subjects main effect are based on the assumption of multisample sphericity. Type I error rates and power are reported for the F test and two tests designed for use when multisample sphericity is violated: the $\widetilde{\xi}$-adjusted test and the Corrected Improved General Approximation(CIGA) test.The results indicate that even though the F test and the $\widetilde{\xi}$-adjusted test have better power than the CIGA test in some conditions, the F test and the $\widetilde{\xi}$-adjusted test do not control Type I error rates when the design is unbalanced and the F test dose not have a good control of Type I error rates when sphericity assumption is severely violated.

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Simulation analysis of type I error and power for F test and rank transformed F test in $2 times 2$ factorial ANOVA ($2 times 2$ 요인 계획법의 F 검정과 순위 F 검정에 따른 제1종 오류와 검정력 분석에 대한 의태 연구)

  • 최영훈
    • The Korean Journal of Applied Statistics
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    • v.8 no.2
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    • pp.87-97
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    • 1995
  • When there is no main effcts or only one main effect in a $2 \times 2$ factorial design, Type I error rates and power for the rank transformed F test (FR test) for interaction are nearly equal to those of the classical F test. However the power of FR test is quite superior under the exponential distribution rather than the of FR test is quite superior under the exponential distribution rather than the normal distribution. Meanwhile when both main effects are in the model, Type I error rates of FR test, compared with those of F test, decrease as the effect size increases and are dependent on the fashion in which main effects are constructed. In addition, the power of FR test increases as the effect size and the sample size increase and is highly dependent on the manner in which main effects are constructed and the type of population distribution.

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Test Pattern Generation for Combinational Circuits using Inherited Values (전수받은 값을 이용한 조합회로에 대한 검사 패턴 발생)

  • Song, Sang-Hun
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.2
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    • pp.606-615
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    • 1997
  • This paper proposes an dffcient method for test pattern generation.Current test pattern genration systems generate a test vester for fault $F_{i+l}$ independently of the computation previously done for faults F1,F2...,Fi The proposed algorithm generates a test vector for fault $F_{i+l}$ by inheriting the test vector for fault Fi. A new test vector is grnerated from inherited values by gradually changing the inhderited values .The inherited values may partially activate a fauog and propagate the fault signal,Normally,this reduses the number of decision steps and backtracks in the second search.Experimental results for well-Known benchmark circuts show that the proposed algorithm is very efficient with small backtrack kimit;in combination eith other algorithms,it is very efficient for arbitrary backtrack limits.

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The Correlation of VOT and f0 In the Perception of Korean Obstruents (한국어 장애음 지각에서의 VOT와 F0의 상관 관계)

  • Kim Midam
    • Proceedings of the KSPS conference
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    • pp.163-167
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    • 2003
  • The present thesis examines the correlation of VOT and F0 in the three-way distinction of Korean obstruents, conducting production and perception tests. In the production test, one female native speaker of Korean with a Seoul dialect (the author) recorded 15 repetitions of a monosyllabic word list including /ka, kha, k*a, pa, pha, p*a, ta, tha, t*a, ca, cha, c*a/ in random order, VOT and F0 of the following vowels were measured, and the result was significant for the three-way distinction with a strong correlation between VOT and F0, and also in the VOT-F0 plot, no overlapping among the domains was observed. As for the perception test, I manipulated the data recorded in the production test, heightening or lowering their F0 values. In all, 14 subjects (seven males and seven females) participated in the identification test. The result was as follows: the fortis stimuli were not influenced by F0 changes, and the VOT and F0 values at the lenis-aspirated boundary were negatively correlated. From these results I concluded the following: 1) VOT and F0 can distinguish the three domains of Korean obstruents without overlapping; 2) the fortis perception does not need F0 as its acoustic cue; and 3) VOT and F0 in the distinction between the lenis and aspirated are in the phonetic trading relation[2].

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Comparing the performance of likelihood ratio test and F-test for gamma generalized linear models (감마 일반화 선형 모형에서의 가능도비 검정과 F-검정 비교연구)

  • Jo, Seongil;Han, Jeongseop;Lee, Woojoo
    • The Korean Journal of Applied Statistics
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    • v.31 no.4
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    • pp.475-484
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    • 2018
  • Gamma generalized linear models are useful for non-negative and skewed responses. However, these models have received less attention than Poisson and binomial generalized linear models. In particular, hypothesis testing for the significance of regression coefficients has not been thoroughly studied. In this paper we assess the performance of various test statistics for gamma generalized linear models based on numerical studies. Our results show that the likelihood ratio test and F-type test are generally recommended and that the partial deviance test should be avoided in practice.

The Intervention Effect of Cognitive Improvement Program for Elderly with Mild Cognitive Impairment (경도인지장애 노인의 인지향상 프로그램 중재효과)

  • Song, Myeong Kyeong;Kim, Soon Ock;Kim, Chun Suk
    • Journal of Korean Public Health Nursing
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    • v.32 no.1
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    • pp.81-95
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    • 2018
  • Purpose: This study was conducted to identify the effects of a group cognitive improvement program on cognitive function, depression and self-esteem in elderly individuals with mild cognitive impairment. Methods: This was an experimental study that employed a pre-post design of a non-equivalence control group. The subjects were 52 elderly people with mild cognitive impairment, 25 of whom were assigned to the experimental group and 27 to the control group. The program was conducted for a total of 12 sessions for 60 minutes each. Data were analyzed using the ${\chi}2-test$, Fisher's exact test, and Independent t-test with the SPSS 20.0 program. Results: After the intervention, the group who participated showed improvement in all areas of cognitive function based on MMSE-KC (F=26.37, p.<0.001), the Rey Complex Figure Test: copy (F=20.66, p.<0.001), Immediate memory of Seoul Verbal Learning Test-Elderly's version (F=29.68, p.<0.001), delayed memory (F=45.79 p.<0.001), memory recall (F=28.97, p.<0.001), Forward of Digit Span Test (F=9.25, p=.004), backward (F=8.33, p.=0.006), language comprehension (F=13.42, p.<0.001), and digit symbol coding (F=17.74, p.<0.001) relative to the control group. Moreover depression (F=24.09, p.<0.001) was decreased in program participants, whereas self-esteem (F=40.24, p.<0.001) was increased. Conclusion: The program could be a useful intervention because the results show that the group cognitive improvement program has a significant effect on cognitive function, depression and self-esteem in elderly with mild cognitive impairment.

Fusarium spp. Isolated from Seed, Root and Cultivated Soil of Phaseouls vidissimus and Their Pathogenicity (녹두종자, 뿌리와 녹두 재배토양에서 분리된 Fusarium spp.와 병원성)

  • Paik Su Bong;Do Eun Su
    • Korean Journal Plant Pathology
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    • v.3 no.1
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    • pp.8-12
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    • 1987
  • Fusarium oxysporum, F. moniliforme, F. solani, F. equiseti, F. semitectum, and F. sporotrichioides were detected from seeds, roots and cultivated soil of Phaseolous vidissimus collected from Kyung-gi Provincial Rural Development Administration. The rate of seedling desease incidence was $60\%$ by testing of seed germination using a large petri-dish. According to the blotter method, F. moniliforme showed $7\%$ infection at seed-coat and $2\%$ at cotyledon and embryo. Their pathogenicities of F. moniliforme, F. semitectum, F. equiseti, and F. sporotrichioides isolated from seeds were recognized on seedlings by water-agar test tube methods. F. oxysporum and F. solani isolated from infected-roots had their pathogenicity by water-agar test tube method but were weakly pathogenic by soil treatment method. Their pathogenicities of F. oxysporum. F. solani and F. uiseti isolated from cultivated-soil were recognized by water-agar test tube method. These F. oxysporum and equiseti isolates had their pathogenicities but F. solani was weakly pathogenic by soil treatment method.

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Comparison of Alkali-Silica Reactivity for Mortar Bar and Concrete Prism Specimens Using Crushed Aggregates in Korea (국내 쇄석골재를 사용한 모르타르 봉 및 콘크리트 각주 시험편의 알칼리-실리카 반응성 비교)

  • Kim, Seong-Kwon;Yun, Kyong-Ku;Hur, In
    • International Journal of Highway Engineering
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    • v.14 no.5
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    • pp.93-99
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    • 2012
  • PURPOSES: The purpose of this study is to compare the alkali-silica reactivity for mortar bar and concrete prism specimens using crushed aggregates of 5 types in Korea. And the alkali-silica reactivity for those aggregates are measured by chemical test method. METHODS: The alkali-silica reactivity for those aggregates was measured by chemical test method of KS F 2545, mortar-bar test of KS F 2546, accelerated mortar-bar test method of ASTM C 1260 and concrete prism test method of ASTM C 1293, relatively. RESULTS: The alkali-silica reactivity for those aggregates was verified by chemical test of KS F 2546 and accelerated mortar-bar test of ASTM C 1260. However, it was not by mortar-bar test of KS F 2546 and concrete prism test of ASTM C 1293. CONCLUSIONS: The above results showed that relationship among the four test methods were very low. The results from 3 types of test methods using cement-aggregate combinations appeared to be different. Because the environmental conditions of test methods for measuring the alkali-silica reactivity such as equivalent alkali content(external source), humidity, temperature, and times were different though the aggregates were same. Moreover, alkali-silica reactivity showed the biggest impact when alkalis were supplied form outside and exposed to environmental conditions. The accelerated mortar-bar test method seems to be most appropriate test method for concrete structures exposed to alkali environment.