I am trying to do a post-hoc test to compare different types of a variable (levels of pollution, which are coded as 1, 2, 3). When I rerun the tests it gives me a "0 x 0 matrix" error.
p.i <- (d$pollute = 2)
p.m <- (d$pollute = 3)
pairwise.t.test(p.none, p.i, p.adj = "none")
pairwise.t.test(p.none, p.m, p.adj = "none")```