模糊数据的一致性系数

时间:2016-03-03 09:22:30

标签: r algorithm math correlation ranking

我正在尝试调整计算模糊数据的一致性系数的公式。描述它的论文在https://www.researchgate.net/publication/4738093_The_coefficient_of_concordance_for_vague_data

我感兴趣的具体方程是(22)

coefficient of concordance for vague data

有四个观察者(即k = 4)和八个物体(即n = 8)。答案应该是0.7485

我可以用R中的公式来计算肯德尔W的标准方程,但不是这个。我想我只是搞乱了操作的顺序。

在R中,我认为输入值应为:

u <- c(6/7, 4/7, 1, 1/7, 2/7, 3/7, 5/7, 0,
5/7, 4/7, 6/7, 1/7, 2/7, 3/7, 0, 0,
    1, 5/7, 2/7, 0, 2/7, 4/7, 6/7, 1/7,
        5/7, 3/7, 4/7, 0, 2/7, 0, 6/7, 1/7)
v<-c(1/7, 3/7, 0, 6/7, 5/7, 4/7, 2/7, 1,
1/7, 2/7, 0, 5/7, 4/7, 3/7, 0, 6/7,
    0, 2/7, 4/7, 1, 4/7, 3/7, 1/7, 6/7,
        1/7, 3/7, 2/7, 6/7, 4/7, 0, 0, 5/7)

您可以在第320页底部和第321页顶部看到这些值

希望你能帮忙

2 个答案:

答案 0 :(得分:2)

您的矢量是正确的,k = 4和n = 8的值也是正确的。这意味着肯德尔的一致性计算系数存在误差。如果没有显示除here之外的代码,我就无法帮助你。我把执行此计算的电子表格kendall_concordance.ods放进去,所以希望它能为你完成这项工作。我按预期得到了0.7485的结果。

你应该做的是:

1. Build u, v vectors (you have done this)

2. Calculate averages of each column in u and v (2n averages).

3. Subtract 0.5 from all averages and square them (for all av in u:
   av = (av - 1/2)^2, same for v) so they are now distances from
   ideal concordance for each column

4. Sum all 16 distances and multiply by 6(n-1)/(n(n+1))

答案 1 :(得分:0)

我在R中为公式构建了函数,如下所示:

vagueKendall<-function(u,v,n){
  u<-matrix (u, ncol=n, byrow = TRUE)
  v<-matrix (v, ncol=n, byrow = TRUE)
    ## divide by n-1 
  uColNo<-u/(n-1)
  vColNo<-v/(n-1)
    ## take the averages
  colMeansU<-colMeans(uColNo)
  colMeansV<-colMeans(vColNo)
    ## measure the distances from the averages 
  au = (colMeansU - 1/2)^2
  av = (colMeansV - 1/2)^2
    ## calculate component before sum
  outside<-6*(n-1)/(n*(n+1))
    ## sum of squared distances from averages 
  sumSqdDiff<-sum(au+av)
    ## The product of these gives the modified Kendall's W
  W<-outside*sum(au+av)
  return(W)
}

第二个函数将计算此值的p值(我希望):

## Extract p-value function
vagueKendallP<-function(W,k,n){
## Calculate correlation coefficient 
r<-(k*W-1)/(k-1)
## Calculate Chi Squared
Chi<-k*(n-1)*W
## degrees of freedom
df<-n-1
## p-value 
pValue<-pchisq(Chi,df, lower.tail = FALSE)
return(pValue)
}