基于T-test的permutation test
1：R 中进行置换检验的方式有多种，比较典型的就是coin包中的oneway_test函数，但是一个问题是实际问题考虑的可能只是单侧的置换检验的结果，
但是oneway_test计算的默认是双侧的P值，这时的计算最好是用Deducer包中的perm.t.test函数
2：简单的perm.t.test函数的说明
perm.t.test(x,y,statistic=c("t","mean"),alternative=c("two.sided", "less", "greater"), midp=TRUE, B=10000)
x a numeric vector containing the first sample
y a numeric vector containing the second sample
statistic The statistic to be permuted. See details
alternative The alternative hypothesis，可以设置是单侧的还是双侧的假设检验
midp should the mid p-value be used
B The number of monte-carlo samples to be generated
Details
This function performs a two sample permutation test. If the mean is permuted, then the test assumes exchangability between the two samples.
if the t-statistic is used, the test assumes either exchangability or a sufficiently large sample size. Because there is little lost in the way of power,
and the assumptions are weaker, the t-statistic is used by default.
Value
A list with class "htest" containing the following components:
statistic The observed value of the statistic.
p.value the p-value for the test.
method a character string indicating the type of test performed.
data.name a character string giving the name(s) of the data.
B The number of samples generated
alternative the direction of the test
4：例子默认的是以Ttest的方式进行置换检验
perm.t.test(rnorm(100),runif(100,-.5,.5))
rm(list=ls())
x<-c(1,2,3,4,5)
y<-c(100,101,102,103,104)
perm.t.test(y,x,alternative="greater",midp=TRUE, B=1000)
5：使用注意：
a：不同类样本的先后顺序
b：函数perm.t.test处于Deducer包中，在安装Deducer的过程中需要涉及java的环境配置等等，
需要R的版本与Java的版本一致，目前找到的比较好的处理方式参照如下：http://www.cnblogs.com/ohshit/p/6159644.html
处理之后便可以成功library rJava