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排序方式: 共有78条查询结果,搜索用时 6 毫秒
1.
对缺失原始数据的数据资料进行了方差分析。从方差分析的基本原理入手,对基本统计数据进行反向推理,得到处理间和误差项的各项离差平方和、自由度以及均方,从而可以实现缺失原始数据下的方差分析,并编写了SAS程序予以实现整个计算和方差分析过程。 相似文献
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双列杂交育种法配合力统计分析(单变元)的SAS实施 总被引:1,自引:0,他引:1
论述了如何应用SAS过程解决格里芬双列杂交育种法4的配合力计算问题,其中应用了transpose过程、merge语句及统计代换Z=Y+X,并以实例示明具体计算法。此法具有国际普遍适用的价值。 相似文献
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Field trials with perennial crops give rise to repeated measurements taken on the same plot on several occasions. It is important to account for serial correlation among repeated measurements in such trials. This study illustrates the use of mixed models for this purpose. We consider the analysis of trials conducted at several locations and the combination of trials with different starting years. A key issue in the analysis is the distinction between effects of calendar years, which are associated with external environmental variation, and harvest years, which represent internal yield formation processes of the perennial crop. Two methods of two‐stage analysis are compared with single‐stage analysis. It is shown that results of two‐stage analysis are very similar to those of single‐stage analysis, if serial correlation is properly taken into account. Program code for the MIXED procedure of the SAS system is given in an Appendix S1 for all considered cases. 相似文献
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选用了能够用于农药毒力数据机率值分析的通用软件(SAS、SPSS和DPS)和专门程序(Polo、BA和EPA机率值分析程序),以二化螟对三唑磷的室内毒力数据为例,比较分析不同统计分析软件的计算结果。结果表明,当对照组死亡率为0时,6个软件程序计算得到的LD值(LD5、LD50和LD95)、截距和斜率等基本相等,但是LD值的95%置信限有差异。当对照组死亡率不为0时,发现6个程序计算得到的毒力资料数值都有差异,其中LD(LD5、LD50和LD95)、截距和斜率的数值相差较小,但是LD值的95%置信限差异较大。 相似文献
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陈文贤 《华南热带农业大学学报》2003,9(4):5-8
采用国际通用统计软件SAS对香荚兰种苗繁殖在土壤pH值一定及母蔓长度一定时,母蔓在育苗后不同时间的出根、出芽率试验结果进行统计分析。结果表明:当土壤pH值为7.0、母蔓长度为30cm时,母蔓在育苗后不同时间的出根、出芽率较高。 相似文献
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Analysis of Unbalanced Data by Mixed Linear Models Using the mixed Procedure of the SAS System 总被引:2,自引:0,他引:2
Unbalanced data are a common problem in plant research based on designed experiments. Such data are often conveniently analysed using linear mixed models. Recent developments in mixed model theory have been implemented in major packages. This paper describes the use of the mixed procedure of the SAS System for the analysis of designed experiments. Special emphasis is given to the specification of options as depending on the assumed mixed model and on the unbalancedness in the data. In addition, we consider a compact representation of multiple comparisons for unbalanced data (letter display). Two small data sets are used to exemplify the methods. 相似文献
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Robert H. Gulden David Levy-Booth Jeff R. Powell Kari E. Dunfield K. Peter Pauls Clarence J. Swanton 《Soil biology & biochemistry》2007,39(8):1956-1967
Recent advances in molecular techniques have allowed for the routine examination of nucleic acids in environmental samples. Although current methodologies are very sensitive, accurate target DNA quantification from environmental samples remains challenging. To facilitate high-throughput DNA quantification from environmental samples, we developed a novel DNA quantification method based on a non-linear curve-fitting approach to extract additional information from quantitative PCR amplification curves and used the fitted parameters to develop multiple regression standard equations for target DNA quantification. A 3-parameter sigmoidal function performed superior to a 4-parameter Weibull function for generating the multiple regression standard equations. In a verification experiment, target DNA was quantified in a series of ‘unknown’ samples in three soils using this approach and the results were compared to target DNA values determined using corrected and uncorrected Ct-based (threshold cycle) methods. For each method, the deviations from the expected target DNA content were determined. Results clearly showed that over all DNA concentrations, target DNA content determined by the non-linear curve-fitting method was more accurate and more precise than values predicted by all other methods. Analysis of variance conducted on the predicted DNA contents also revealed fewer statistical artifacts with the non-linear curve fitting method compared to the conventional Ct-based methods. The novel approach described here is accurate, inexpensive, and very amenable for automation and high-throughput applications. 相似文献