ethanol <-
structure(list(treatment = structure(c(3L, 3L, 3L, 3L, 3L, 3L, 
3L, 3L, 3L, 3L, 3L, 3L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L), .Label = c("ethyl_cellulose", "pure_ethanol", "pure_ethanol_16x"
), class = "factor"), regress = structure(c(2L, 2L, 2L, 2L, 1L, 
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 
2L, 2L, 1L), .Label = c("no", "yes"), class = "factor")), row.names = c(NA, 
-24L), class = c("tbl_df", "tbl", "data.frame"))