摘要： For most hypothesis tests, we start with the assumptions and work forward to derive the sampling distribution of the test statistic under the null hypothesis. For permutation tests we will reverse the procedure, since the sampling distribution involves the permutations which give the procedure its n 阅读全文

摘要： Randomization Tests Constrained ordination methods such as CCA and RDA find the ' best possible' relationship (defined in a mathematical sense) between species composition and the environment. Therefo... 阅读全文

摘要： Randomization Tests We will begin with randomization tests, because they are closer in intent to more traditional parametric tests than are bootstrapping procedures. Their primary goal is to test some... 阅读全文

摘要： Randomization Tests (1 of 6) Most distribution-free tests are based on the principle of randomization. The best way to understand the principle of randomization is in terms of a specific example of a ... 阅读全文

摘要： The Cauchy–Lorentz distribution, named after Augustin Cauchy and Hendrik Lorentz, is a continuous probability distribution. As a probability distribution, it is known as the Cauchy distribution, while... 阅读全文

摘要： In probability theory, a log-normal distribution is a probability distribution of a random variable whose logarithm is normally distributed. If X is a 阅读全文

摘要： betarnd 贝塔分布的随机数生成器 binornd 二项分布的随机数生成器 chi2rnd 卡方分布的随机数生成器 exprnd 指数分布的随机数生成器 frnd F分布的随机数生成器 gamrnd 伽玛分布的随机数生成器 geornd 几何分布的随机数生成器 hygernd 超几何分布的随机数生成器 lognrnd 对数正态分布的随机数生成器 nbinrnd 负二项分布的随机数生成器 ncf... 阅读全文

摘要： Poisson分布 概率密度函数 poisspdf(x,lamda) 分布函数poisscdf(X,lamda) 逆概率分布函数poissinv(F,lamda) x=[0:15]'; y1=[]; y2=[]; lam1=[1,2,5,10]; for i=1:length(lam1) y1=[y1,poisspdf(x,lam1(i))]; y2=[y2,poisscdf(x,lam1(i... 阅读全文

摘要： 假定a为某指标在10个样本中的值，5个一组，看以两组均值的差为例（统计量），随机置换检验程序 example: a: 230 -1350 -1580 -400 -760 970 110 -50 -190 -200 v1=sum(a(1:5))/5; v2=sum(a(6:10))/5; T=abs(v1-v2); x=perms(a); %矩阵a的全排列（随机全排列） v11=(x(:,1)+x(... 阅读全文

摘要： 工欲善其事，必先利其器！ 数据分析也好，统计分析也好，数据挖掘也好、商业智能也好都需要在学习的时候掌握各种分析手段和技能，特别是要掌握分析软件工具！在数据分析领域，都有哪些软件分析工具呢？如何选择呢？其实很多领域或者说分析方法都有相应的软件工具，只要你想找就应该能够找到！ 这里把软件分成纵横四个层次的的象限图来表达！ 第一维度：数据存储层——>数据报表层——>数据分析层——>数据展现层 第二维度：... 阅读全文