[R language Statistics] frequency tables

The frequency tables are a very basic and important concept in statistics, and we will explain its basic usage here.

First we need to load the data and see the basic information of the data

Install.packages (' vcd ') #安装vcd包, where available data arthritislibrary (VCD) are loaded into the required thread pack:grid> Head (arthritis) ################     ################################ #ID Treatment Sex age Improved1 treated Male Some2 29 treated Male  None3 treated Male-None4-treated Male-Marked5-treated Male, Marked6 treated Male Marked> Class (arthritis) ################################################[1] "Data.frame" > Summary (    Arthritis) ############################################# #ID treatment Sex age improved Min.   : 1.00 placebo:43 female:59 Min.                            : 23.00 none:42 1st qu.:21.75 treated:41 male:25 1st qu.:46.00 some:14 median:42.50                            median:57.00 marked:28 mean:42.50 mean:53.36 3rd qu.:63.25   3rd qu.:63.00 Max.   : 84.00 Max. : 74.00

As seen from the results, arthritis is the data of a data.frame structure. Where ID and age are data of type numeric, the other three are data of type factor.

Create a one-dimensional column table

> a<-table (arthritis$improved) #创建一维列联表 > class (a)                    #查看变量a的类型 [1] "table" > Anone   Some Marked     14     

As can be seen from the results, it is the following table

None	Some	Marked
42	14	28

Create a two-dimensional column table

> b<-table (arthritis$sex,arthritis$improved) > class (b) [1] "table" > B                 None Some Marked  Female  Male    2      6

The result is the following table

	None	Some	Marked
Female	25	12	22
Male	17	2	6

We can also convert a one-dimensional list of table A and two-dimensional column table B into a percentage form

> prop.table (a)     none      Some    Marked 0.5000000 0.1666667 0.3333333 > prop.table (b)                       none       Some     Marked  Female 0.29761905 0.14285714 0.26190476  Male   0.20238095 0.02380952 0.07142857

add a marginal to table and

> Addmargins (a) ####################################  None   Some Marked    Sum     28     > Addmargins (b) ####################################                 None Some Marked sum  Female   -  Male    2      6  sum  84> addmargins (Prop.table (a)) #########################     None      Some    Marked       Sum 0.5000000 0.1666667 0.3333333 1.0000000 > Addmargins (prop.table (b)) #########################                       None       Some     Marked        Sum  Female 0.29761905 0.14285714 0.26190476 0.70238095  Male   0.20238095 0.02380952 0.07142857 0.29761905  Sum    0.50000000 0.16666667 0.33333333 1.00000000

add only a portion of the marginal and

> Addmargins (prop.table (b), 1)                       None       Some     Marked  Female 0.29761905 0.14285714 0.26190476  Male   0.20238095 0.02380952 0.07142857  Sum    0.50000000 0.16666667 0.33333333> addmargins (prop.table (b), 2)                       None       Some     Marked        Sum  Female 0.29761905 0.14285714 0.26190476 0.70238095  Male   0.20238095 0.02380952 0.07142857 0.29761905

Reference: R language Combat

Reprint Please specify source: http://blog.csdn.net/zhyoulun/article/details/46433163

[R language Statistics] frequency tables