Question

> data(infert, package = "datasets")
> tt = xtabs(~education + induced + spontaneous, data = infert)
> ftable(tt)
                  spontaneous  0  1  2
education induced                     
0-5yrs    0                    2  1  1
          1                    1  0  1
          2                    6  0  0
6-11yrs   0                   46 19 13
          1                   15  9  3
          2                   10  5  0
12+ yrs   0                   19 27 15
          1                   29  7  3
          2                   13  3  0

xtabs生成了很好的表格，但我想知道是否有办法让它显示行总计和列总数。此外，它是否有可能显示某种频率，即N /行总数和N /列总数？

我在CrossTable包中尝试过gmodels函数，效果非常好。但是，它似乎只适用于2个变量，而我想一次比较2个变量。

> library(gmodels)
> CrossTable(infert$education, infert$induced, expected = TRUE)


   Cell Contents
|-------------------------|
|                       N |
|              Expected N |
| Chi-square contribution |
|           N / Row Total |
|           N / Col Total |
|         N / Table Total |
|-------------------------|


Total Observations in Table:  248 


                 | infert$induced 
infert$education |         0 |         1 |         2 | Row Total | 
-----------------|-----------|-----------|-----------|-----------|
          0-5yrs |         4 |         2 |         6 |        12 | 
                 |     6.919 |     3.290 |     1.790 |           | 
                 |     1.232 |     0.506 |     9.898 |           | 
                 |     0.333 |     0.167 |     0.500 |     0.048 | 
                 |     0.028 |     0.029 |     0.162 |           | 
                 |     0.016 |     0.008 |     0.024 |           | 
-----------------|-----------|-----------|-----------|-----------|
         6-11yrs |        78 |        27 |        15 |       120 | 
                 |    69.194 |    32.903 |    17.903 |           | 
                 |     1.121 |     1.059 |     0.471 |           | 
                 |     0.650 |     0.225 |     0.125 |     0.484 | 
                 |     0.545 |     0.397 |     0.405 |           | 
                 |     0.315 |     0.109 |     0.060 |           | 
-----------------|-----------|-----------|-----------|-----------|
         12+ yrs |        61 |        39 |        16 |       116 | 
                 |    66.887 |    31.806 |    17.306 |           | 
                 |     0.518 |     1.627 |     0.099 |           | 
                 |     0.526 |     0.336 |     0.138 |     0.468 | 
                 |     0.427 |     0.574 |     0.432 |           | 
                 |     0.246 |     0.157 |     0.065 |           | 
-----------------|-----------|-----------|-----------|-----------|
    Column Total |       143 |        68 |        37 |       248 | 
                 |     0.577 |     0.274 |     0.149 |           | 
-----------------|-----------|-----------|-----------|-----------|


Statistics for All Table Factors


Pearson's Chi-squared test 
------------------------------------------------------------
Chi^2 =  16.53059     d.f. =  4     p =  0.002383898

Answer 1

您可以使用prop.table生成频率表，并使用addmargins

添加边距

data(infert, package='datasets')
prop.table(addmargins(xtabs(~education + induced + spontaneous, data=infert)))

Answer 2

您和@ajerneck可能喜欢以下解决方案：

printProp.xtab<-function(xtab,fmt='%s (%1.2f%%)',big.mark=',',na.print="NA",...) {
  ## PURPOSE: print an xtab with percentages in
  ## parentheses in addition to counts at every value.
  ## TODO: alignment the percentages at the decimal point.
  xtab.am<-addmargins(xtab)
  xtab.pt.am<-addmargins(prop.table(xtab,...))
  res<-sprintf(fmt,format(xtab.am,big.mark=big.mark),100*xtab.pt.am)
  attributes(res)<-attributes( xtab.am)
  print(quote=FALSE
       ,na.print=na.print
        ,res)
}

在示例数据上使用它：

printProp.xtab(xtabs(~education + induced + spontaneous, data=infert))
, , spontaneous = 0

         induced
education 0            1            2            Sum         
  0-5yrs    2 (0.81%)    1 (0.40%)    6 (2.42%)    9 (3.63%) 
  6-11yrs  46 (18.55%)  15 (6.05%)   10 (4.03%)   71 (28.63%)
  12+ yrs  19 (7.66%)   29 (11.69%)  13 (5.24%)   61 (24.60%)
  Sum      67 (27.02%)  45 (18.15%)  29 (11.69%) 141 (56.85%)

, , spontaneous = 1

         induced
education 0            1           2           Sum         
  0-5yrs    1 (0.40%)    0 (0.00%)   0 (0.00%)   1 (0.40%) 
  6-11yrs  19 (7.66%)    9 (3.63%)   5 (2.02%)  33 (13.31%)
  12+ yrs  27 (10.89%)   7 (2.82%)   3 (1.21%)  37 (14.92%)
  Sum      47 (18.95%)  16 (6.45%)   8 (3.23%)  71 (28.63%)

, , spontaneous = 2

         induced
education 0            1           2           Sum         
  0-5yrs    1 (0.40%)    1 (0.40%)   0 (0.00%)   2 (0.81%) 
  6-11yrs  13 (5.24%)    3 (1.21%)   0 (0.00%)  16 (6.45%) 
  12+ yrs  15 (6.05%)    3 (1.21%)   0 (0.00%)  18 (7.26%) 
  Sum      29 (11.69%)   7 (2.82%)   0 (0.00%)  36 (14.52%)

, , spontaneous = Sum

         induced
education 0            1            2            Sum          
  0-5yrs    4 (1.61%)    2 (0.81%)    6 (2.42%)   12 (4.84%)  
  6-11yrs  78 (31.45%)  27 (10.89%)  15 (6.05%)  120 (48.39%) 
  12+ yrs  61 (24.60%)  39 (15.73%)  16 (6.45%)  116 (46.77%) 
  Sum     143 (57.66%)  68 (27.42%)  37 (14.92%) 248 (100.00%)

如何使用xtabs创建频率表

2 个答案: