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Posté le: Jeu 26/04/18 04:05 Sujet du message: robkelley 


The signed rank test can be used to make inferences about the median of an unknown distribution function F(x) under the assumption that the probability density (mass) function is symmetric. If the distribution is symmetric http://www.cheapnfljerseysredskin.com/dustinhopkins/ , then the median of the distribution is equal to the mean of the distribution, and they can both be denoted by μ = F −1 (0.5). The sign test can also be used to provide inferences about the median without the necessity of making any assumptions about the distribution function F(x). However, the motivation behind the use of the signed rank test is that it provides a more precise analysis in situations where the distribution function can reasonably be taken to be symmetric.
The assumption of symmetry may be justified by an experimenter through observation or through an understanding of the nature of the data. For example, a simple histogram of the data may be sufficient to indicate that the assumption of symmetry is not inappropriate. In other cases, the experimenter may expect that the randomness in the data is composed primarily of a measurement error that can reasonably be expected to be distributed symmetrically. The additional precision of the signed rank test over the sign test is achieved through the consideration of the magnitudes of the deviations of the observed data values xi from the hypothesized median valueμ0. The sign test is performed by looking at whether an observation xi is less than μ0 or is greater than μ0. The signed rank test not only takes into account this information but also considers
xi − μ0
Where, the magnitude of the distance is between xi and μ0. The magnitudes provide additional information about the location of the median when the distribution is assumed to be symmetric. The signed rank test provides a useful middle ground between the sign test and a fully parametric test such as the ttest under a normal distributional assumption. The sign test is a very general procedure that requires no distributional assumptions. The signed rank test utilizes the additional information provided by an assumption that the distribution is symmetric and allows more precise inferences to be made about the mean of the distribution in this case. This assumption of symmetry can often be justified by an experimenter and provides a middle ground that is less restrictive than the exact specification of a symmetric distribution such as the normal distribution.
The choice of which inference method to adopt should be made on the basis of which set of assumptions are reasonable, and histograms or other data plots may be useful to investigate the form of the distribution. The experimenter should make use of any reasonable assumptions http://www.cheapnfljerseysredskin.com/tressway/ , so that for example, the signed rank test should be used in preference to the sign test when the assumption of symmetry can be justified. Remember that the central limit theorem implies that the ttest (or equivalently the ztest) can be used for large enough sample sizes regardless of the actual distribution of the data observations, although the sign test and the signed rank test in practice often provide as precise an inference as the ttest and may still be preferred. TIANJIN, China, Oct. 14 (Xinhua)  Following are the medalists at the sixth East Asian Games here on Monday:
Soccer
Men's
Gold: DPR Korea
Silver: South Korea
Bronze: Japan
Basketball
Men's
Gold: Chinese Taipei
Silver: China
Bronze: South Korea
Baseball
Gold: Japan
Silver: South Korea
Bronze: Chinese Taipei
Cycling
Women's track 500m time trial
Gold: Zhong Tianshi, China
Silver: Lee Wai Sze, Hong Kong http://www.cheapnfljerseysredskin.com/shawnlauvao/ , China
Bronze: Kayono Maeda, Japan
Men's track 1km time trial
Gold: Yudai Nitta, Japan
Silver: Zhang Miao, China
Bronze: Hsiao Shihhsin, Chinese Taipei
Men's track individual pursuit
Gold: Kim Hongki, South Korea
Silver: Eiya Hashimoto, Japan
Bronze: Cheung King Lok http://www.cheapnfljerseysredskin.com/bashaudbreeland/ , Hong Kong, China
Women's track individual pursuit
Gold: Huang Dongyan, China
Silver: Jiang Fan, China
Bronze: Huang Tingying, Chinese Taipei
Judo
Women's 4548kg
Gold: Kim Sol Mi, DPR Korea
Silver: Cho Ara, South Korea
Bronze: Yamazaki Tamami http://www.cheapnfljerseysredskin.com/spencerlong/ , Japan
Bronze: Qiu Xiangting, Chinese Taipei
Women's 4852kg
Gold: Takumi Miyakawa, Japan
Silver: Cha Ok Song, DPR KoreaP Bronze: Jung Eunjung, South Korea
Bronze: Baldinnyam baterdene, Mongolia
Women's 5257kg
Gold: Kim Jandi, South Korea
Silver: Liu Yang http://www.cheapnfljerseysredskin.com/morganmoses/ , China
Bronze: Ri Un Ju, DPR Korea
Bronze: Hirai Nozomi, Japan
Men's 5560kg
Gold: Kim Wonjin, South Korea
Silver: tang Xiaolong, China
Bronze: Ryo Kawabata, Japan
Bronze: Tsai Mingyen, Chinese Taipei
Men's 6066kg
Gold: Morishita Jumpei http://www.cheapnfljerseysredskin.com/jamisoncrowder/ , Japan
Silver: Hyon Song Chol, DPR Korea
Bronze: Hwang Bobae, South Korea
Bronze: Chien Chiahung, Chinese Taipei
Men's 6673kg
Gold: Bang Guiman, South Korea
Silver: Takeshi Doi, Japan
Bronze: Hong Kuk Hyon, DPR Korea
Bronze: Khadbaatar Narankhuu http://www.cheapnfljerseysredskin.com/masonfoster/ , Mongolia
Swimming
Women's 50m freestyle
Gold: Tang Yi, China
Silver: Siobhan Bernadette Haughey, Hong Kong, China
Bronze: Lee Jaeyoung, South Korea
Men's 50m freestyle
Gold: Ning Zetao, China
Silver: Yuki Kawachi, Japan
Bronze: Geoffrey Robin Cheah http://www.cheapnfljerseysredskin.com/deshazoreverett/ , Hong Kong, China
Men's 100m butterfly
Gold: Kohei Kawamoto, Japan
Silver: Shi Feng, China
Bronze: Masayuki Umemoto, Japan
Women's 200m breaststroke
Gold: Mio Motegi, Japan
Silver: Shi Jinglin, China
Bronze: Runa Imai http://www.cheapnfljerseysredskin.com/robkelley/ , Japan
Women's 400m individual medley
Gold: Chen Xinyi, China
Silver: Sakiko Shimizu, Japan
Bronze: Kim Seoyeong, South Kore. 

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