Hello,
Marlin Keith Cox wrote:
I need a two sample t.test between M and F. The data are arranged in one
column, x. Cant seem to figure how to run a two sample t.test. Not really
sure what this output is giving me, but there should be no difference
between M and F in the example, but summary p-value indicates this.
How can I run a two sample t.test with data in one column.
x=rep(c(1,2,3,4),2)
y=rep(c("M","M","M","M","F","F","F","F"))
data<-cbind(x,y)
t.test(x,by=list(y))
Several issues:
First, your usage of cbind makes 'data' a matrix of type character, R no
longer sees your numeric x. You most likely want a data.frame (Which
can contain multiple types) instead of a matrix (which has one type of
data), so replace line 3 (and "data" is a function and argument name, so
let's call it something else) with
df <- data.frame(x, y)
I don't see the "by" argument documented anywhere in ?t.test.
I do see the "formula" argument, documented as:
formula: a formula of the form ‘lhs ~ rhs’ where ‘lhs’ is a numeric
variable giving the data values and ‘rhs’ a factor with two
levels giving the corresponding groups.
So try,
t.test(x ~ y, data = df)
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