使用apply (按行)返回数据计算t-test本质上是恒定的。

Question

我试着用两个值进行t检验：

1和n.

这样做是可行的：

a <- c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
     8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97, 8.97)

或

a <- rep(c(1, 8.97), each = 15)

以及：

t.test(x = a, mu = 2.33, alternative = "greater")

    One Sample t-test

data:  a
t = 3.5879, df = 29, p-value = 0.0006046
alternative hypothesis: true mean is greater than 2.33
95 percent confidence interval:
 3.727653      Inf
sample estimates:
mean of x 
    4.985 

是的，但是：

variavel <- seq(from = 1, to = 9, by = .01)

df <- data.frame(fix1 = 1, fix2 = 1, fix3 = 1, fix4 = 1, fix5 = 1, fix6 = 1, fix7 = 1, fix8 = 1, fix9 = 1, fix10 = 1, fix11 = 1, fix12 = 1, fix13 = 1, fix14 = 1, fix15 = 1, 
               ge1 = variavel, ge2 = variavel, ge3 = variavel, ge4 = variavel, ge5 = variavel, ge6 = variavel, ge7 = variavel, ge8 = variavel, ge9 = variavel, ge10 = variavel, ge11 = variavel, ge12 = variavel, ge13 = variavel, ge14 = variavel, ge15 = variavel
               )

当我去计算每一行的测试并获得p-value时，

apply(X = df, MARGIN = 1, FUN = function(x) {
  t.test(x = x, mu = 2.33, alternative = "greater")$p.value
})    

它给了我一个错误：

错误在t.test.default中(x= x，mu = 2.33)：数据本质上是恒定的

会发生什么？

Answer 1

您的第一行是不变的，因为这是一个错误，所以其余的数据从未被测试过。

table(unlist(df[1,]))
#  1 
# 30 

你有两个选择：

1. 在计算中省略了第1行：

头(x= df-1，边距= 1，FUN =函数(X){ t.test(x = x，mu = 2.33，alternative =“大”)$p.value})#2 3 4 5 6 7#1 1 1

1. 在循环中捕获它：

tryCatch(t.test(x = x，mu = 2.33，alternative =“大”)$p.value，error = function(e) NA_real_})# 1 NA 1 1 1