search for: yohai

Displaying 3 results from an estimated 3 matches for "yohai".

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2009 Dec 27
3
help: creating a unified histogram
...ave multiple bars: one representing each matrix, with different colored bars for example to distinguish between the matrices). I couldn't find a function doing that involving "hist", "plot" nor other plotting functions. Is there a function which does this? Thank you, Yael Yohai (Bioinformatics research) [[alternative HTML version deleted]]
2010 Dec 13
1
Wrong contrast matrix for nested factors in lm(), rlm(), and lmRob()
...te() generate the correct estimates. (3) If one uses lm.fit() and lmRob.fit.compute() directly in this way, then, given that one is warned against doing so, what are the dangers? (4) According to cran.r-project.org/web/views/Robust.html, lmRob() "makes use of the M-S algorithm of Maronna and Yohai (2000), automatically when there are factors among the predictors (where S-estimators (and hence MM-estimators) based on resampling typically badly fail)." Is there an alternative program that uses the M-S algorithm, if lmRob() or lmRob.fit.compute() cannot be made to work? ----------------...
2009 May 26
2
(OT) Does pearson correlation assume bivariate normality of the data?
...orrelation in Huber 1981, 2004) - the sample data could come from just about any bivariate distribution (Wikipedia [2][3] and associated reference) - the coefficient is (very) not robust to univariate outliers (e.g., Huber 1981), and to multivariate outliers (?rrcov::maryo with data from Marona and Yohai 1998) 2. Assessing whether the correlation is significantly different from zero (using a statistic following the t distribution): - the data should come from independent normal distributions (?cor.test) - at least one of the marginal distributions is normal (Wilcox 2005) Surprisingly (to me) many...