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当所有值都在一列中时,如何在R中进行配对t检验?

t-test r

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Sergio Nolazco · 技术社区 · 7 年前

在per中形成配对t检验的数据帧的常见格式是将给定的测量值分成两列,以便每行表示相同的受试者或个体。例如:

 > #     Before     After
    > #1      31        32
    > #2      22        34
    > #3      41        35

然而,这并不总是在数据帧中呈现数据的情况。

我有一个数据帧,它的结构非常常见,如下所示:

 subject <- c("A1", "A2" ,"A1" ,"A3" ,"A3" ,"A2")
    value <- c(34, 43, 25, 43, 54, 22)
    group <- c("before", "after", "after", "after", "before", "before")

    mydata <- data.frame(subject, value, group)

    #  subject value  group
    #1      A1    34 before
    #2      A2    43  after
    #3      A1    25  after
    #4      A3    43  after
    #5      A3    54 before
    #6      A2    22 before

那么,基于这个数据框架,我怎样才能在R中进行双侧配对t检验呢?

1 回复 | 直到 7 年前

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2

s__ 7 年前

一些R基函数的数据格式从长到宽呢

# reshape from long to wide
mydata_wide <- reshape(mydata, idvar = "subject", timevar = "group", direction = "wide")

# rename columns
colnames(mydata_wide)[2] <-"before"
colnames(mydata_wide)[3] <-"after"

mydata_wide
  subject before after
1      A1     34    25
2      A2     22    43
4      A3     54    43

# t-test
 t.test(mydata_wide$before,
       mydata_wide$after,
       paired=TRUE,
       conf.level=0.95)