structure(list(study = c("1", "1", "2", "2", "3", "3", "3"), 
    treatment = c("1", "3", "1", "2", "1", "2", "4"), mean = c(-1.22, 
    -1.53, -0.7, -2.4, -0.3, -2.6, -1.2), std.err = c(0.504, 
    0.439, 0.282, 0.258, 0.505, 0.51, 0.478)), row.names = c(NA, 
-7L), class = "data.frame")