stem_cell <-
structure(list(trmt = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 
1L, 1L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L), .Label = c("ctrl", 
"esc"), class = "factor"), before = c(35.25, 36.5, 39.75, 39.75, 
41.75, 45, 47, 52, 52, 29, 29.5, 34, 35, 35.25, 42.5, 44, 49.25, 
53.75), after = c(29.5, 29.5, 36.25, 38, 37.5, 42.75, 39, 45.25, 
52.25, 31, 43.75, 36, 41.5, 39.5, 40, 45.75, 55.25, 51)), row.names = c(NA, 
-18L), class = c("tbl_df", "tbl", "data.frame"))