391,091 research outputs found
Maximally selected chi-square statistics and umbrella orderings
Full text linkBinary outcomes that depend on an ordinal predictor in a non-monotonic way are common in medical data analysis. Such patterns can be addressed in terms of cutpoints: for example, one looks for two cutpoints that define an interval in the range of the ordinal predictor for which the probability of a positive outcome is particularly high (or low). A chi-square test may then be performed to compare the proportions of positive outcomes in and outside this interval. However, if the two cutpoints are chosen to maximize the chi-square statistic, referring the obtained chi-square statistic to the standard chi-square distribution is an inappropriate approach. It is then necessary to correct the p-value for multiple comparisons by considering the distribution of the maximally selected chi-square statistic instead of the nominal chi-square distribution. Here, we derive the exact distribution of the chi-square statistic obtained by the optimal two cutpoints. We suggest a combinatorial computation method and illustrate our approach by a simulation study and an application to varicella data
Monotonicity of Chi-square Test Statistics
Full text linkThis paper establishes monotonicity of the chi-square test statistic. As the more efficient parameter estimator is plugged into the test statistic, the degrees of freedom of the resulting chi-square test statistic monotonically increase.
Master's Degree Recital: Mi Hyun Chi, piano
No full textMs. Chi is a student of Mary NorrisPartita II in C Minor, Bach -- Sonata pour piano (1924), Stravinsky -- Concerto no. 2 in F Minor, Op. 21, Chopi
Maximally selected chi-square statistics and binary splits of nominal variables
Full text linkWe address the problem of maximally selected chi-square statistics in the case of a binary Y variable and a nominal X variable with several categories. The distribution of the maximally selected chi-square statistic has already been derived when the best cutpoint is chosen from a continuous or an ordinal X, but not when the best split is chosen from a nominal X. In this paper, we derive the exact distribution of the maximally selected chi-square statistic in this case using a combinatorial approach. Applications of the derived distribution to variable selection and hypothesis testing are discussed based on simulations. As an illustration, our method is applied to a pregnancy and birth data set
Establishment and characterization of a continuous cell line (GF-1) derived from grouper, Epinephelus coioides (Hamilton): a cell line susceptible to grouper nervous necrosis virus (GNNV)
No full textWen-Chi Chang Oboe Recital Program Notes
No full textThe essay is the program notes of Wen-Chi Chang`s Oboe Recital which was performed on May 9th, 2019. The recital includes four different periods of oboe repertoire, baroque period, classical music period, romantic music period, and modern music period. The recital opened with Antonio Lucio Vivaldi: Oboe Concerto in D Major, RV. 453, Vivaldi was the most important Italian composer and violinist in the Baroque period. His numerous works are in a great astonishment which are including various genres. The second peice is Domenico Cimarosa: Oboe Concerto in C Major, Cimarosa is the most famous Italian opera composer in the 18th century. His opera works are mainly comedy.
\ue3\ue3 The second half of the recital was opened with Charles Camille Saint-Sa\uc3\uabns: Sonata for oboe and Piano, Op. 166, Saint-Sa\uc3\uabns was a French composer, keyboardist and music educator. He has created many important musical works and has a profound influence on future generations. And ended was Paul Hindemith: Sonata for Oboe and Piano, Hindemith was the most representative German composer in the early twentieth century, and an outstanding music performer and music educator. In this program notes article, I will use these four musical works as the topic to overview the life of the four composers, the background of the music composition and the interpretation of each works
Correspondence and Photograph from Ernest W. Wright to Dr. C. A. Bacote, August 30, 1977
No full textCorrespondence between Ernest W. Wright (Employment Security Agency, Georgia Department of Labor) and Dr. C. A. Bacote, 30 August 1977. Enclosed 8"x10" photograph circa 1955, depicting voter registration participants. Written on Verso: "Left to Right: (Seated): Dr. Clarence A. Bacote, Dr. William Hale, Mr. Ron Harris? Dr. Robert Brisbane (Standing): Mr. Michael? Mr. C. A. Scott? Mr. Milton White"
Maximally selected chi-square statistics for at least ordinal scaled variables
Full text linkThe association between a binary variable Y and a variable X with an at least ordinal measurement scale might be examined by selecting a cutpoint in the range of X and then performing an association test for the obtained 2x2 contingency table using the chi-square statistic. The distribution of the maximally selected chi-square statistic (i.e. the maximal chi-square statistic over all possible cutpoints) under the null-hypothesis of no association between X and Y is different from the known chi-square distribution. In the last decades, this topic has been extensively studied for continuous X variables, but not for non-continuous variables with an at least ordinal measurement scale (which include e.g. classical ordinal or discretized continuous variables). In this paper, we suggest an exact method to determine the distribution of maximally selected chi-square statistics in this context. This novel approach can be seen as a method to measure the association between a binary variable and variables with an at least ordinal scale of different types (ordinal, discretized continuous, etc). As an illustration, this method is applied to a new data set describing pregnancy and birth for 811 babies
HIV and tuberculosis in Ho Chi Minh City, Vietnam, 1997-2002.
Full text linkIn Ho Chi Minh City, Vietnam, reporting rates for tuberculosis (TB) are rising in an emerging HIV epidemic. To describe the HIV epidemic among TB patients and quantify its impact on rates of reported TB, we performed a repeated cross-sectional survey from 1997 through 2002 in a randomly selected sample of inner city TB patients. We assessed effect by adjusting TB case reporting rates by the fraction of TB cases attributable to HIV infection. HIV prevalence in TB patients rose exponentially from 1.5% to 9.0% during the study period. Young (<35 years), single, male patients were mostly affected; injection drug use was a potent risk factor. After correction for HIV infection, the trend in TB reporting rates changed from a 1.9% increase to a 0.4% decrease per year. An emerging HIV epidemic, concentrated in young, male, injection drug users, is responsible for increased TB reporting rates in urban Vietnam
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