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11.
Julio M. Singer Frederico Z. Poleto Patrícia Rosa 《Biometrical journal. Biometrische Zeitschrift》2004,46(4):460-473
We compare two models for the analysis of repeated ordinal categorical data: the classical parametric model for means of scores assigned to the categories of the response variable and a nonparametric model based on relative effects derived from the marginal distribution functions of the response. An example in the field of Dentistry is used to illustrate and to compare the models. We also consider a simulation study to evaluate the type‐I error rates and the power of tests under both models in a balanced design setup. The simulation results suggest that both approaches behave similarly for equally spaced scores but may perform differently otherwise. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
13.
I. Hoeschele 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,76(2):311-319
Summary Statistical techniques for detection of major loci and for making inferences about major locus parameters such as genotypic frequencies, effects and gene action from field-collected data are presented. In field data, major genotypic effects are likely to be masked by a large number of environmental differences in addition to additive and nonadditive polygenic effects. A graphical technique and a procedure for discriminating among genetic hypotheses based on a mixed model accounting for all these factors are proposed. The methods are illustrated by using simulated data.Journal Paper No. J-12733 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1901 相似文献
14.
On nonparametric discrimination using density differences 总被引:2,自引:0,他引:2
15.
Regression analysis based on stratified samples 总被引:1,自引:0,他引:1
16.
Estimation in linear models with censored data 总被引:1,自引:0,他引:1
17.
Principal component analysis of compositional data 总被引:7,自引:0,他引:7
18.
H. Preuschoft 《Human Evolution》1989,4(2-3):145-156
The variation of body shape among prosimians is reviewed. Special emphasis is placed on the selective advantages, that is
the mechanical reasons, to which variants of the locomotor apparatus can be traced back.
There are differences found in the cheiridia, but at present they cannot be explained in terms of mechanics; there is nearly
no knowledge about the mechanical meaning of their diversity. Myological characteristics of taxa can be explained mechanically,
but this has not yet been done.
Well known are variations of body proportions. These discriminate higher taxa, and are largely coincident with the often-used
locomotor categories. In spite of this, there are only few sound arguments about the real biomechanic value of characteristic
proportions for a given locomotor mode. What is known on this field, is reviewed. Progress can be made only, if the mechanical
conditions, set by postural behavior and locomotion, are understood completely.
The subtle distinctions between lower taxonomic units can normally be identified only on the basis of detailed and quantified
analyses of movements on one hand, and of biometrics on the other. In the few cases in which such studies have been made,
the differences of morphology fit to the mechanical requirements of locomotion which also differ only in quantitative details. 相似文献
19.
B. Gasser M. Toussaint R. Luthringer J. P. Macher R. Cerf 《Journal of biological physics》1996,22(4):209-225
Attempts to demonstrate low-dimensional attractor behaviour in the analysis of electroencephalographic (EEG) signals meet with difficulties that in part stem from a departure from single-system dynamics. In order to address this problem, the -waves can be extracted by digital filtering or by wave separation; these two techniques are compared in order to specify the conditions in which finite impulse response (FIR) bandpass filters can be used. The comparison was made using 18 EEG records of 3 min duration under resting conditions (6 subjects, 3 records per subject: prior to apomorphine administration, then 90 min and 150 min post-treatment). No presence of low-dimensional dynamic episodes in -signals was observed without digital processing. Sixty 5 s sections showing attractor behaviour were found after filtering and twenty five 5 s sections after wave separation. The mean correlation dimension was calculated for each experimental condition and for 4 subjects, in order to observe the temporal profile of the drug. When attractors were found after wave separation, bandpass filtering then also showed attractor behaviour, with the same temporal profile. However, the reverse is not true: attractors were found after bandpass filtering that were not present after wave separation; in this case the results deserve confirmation, although the temporal profiles for all cases in which attractors were found after filtering remained comparable. 相似文献
20.
After considering the need for quality control in NAA, the concept of quality in NAA procedures themselves is discussed, and
some important factors identified. Two approaches to improve quality are then described in more detail. The first concerns
the unique ability of NAA using different isotopic reactions and different modes (INAA/RNAA) to provide independent data sets
in the same laboratory, thus allowing internal validation or crosschecking. The second discusses the need for chemical yield
measurements in RNAA and the advantages of the radioisotopic tracer technique. Some recent advances and further possibilities
for this use of tracers are listed. 相似文献