structure(list(study = c("1", "1", "2", "2", "3", "3", "3", "4", 
"4", "5", "5", "6", "6", "7", "7"), treatment = c("1", "3", "1", 
"2", "1", "2", "4", "3", "4", "3", "4", "4", "5", "4", "5"), 
    mean = c(-1.22, -1.53, -0.7, -2.4, -0.3, -2.6, -1.2, -0.24, 
    -0.59, -0.73, -0.18, -2.2, -2.5, -1.8, -2.1), std.err = c(0.504, 
    0.439, 0.282, 0.258, 0.505, 0.51, 0.478, 0.265, 0.354, 0.335, 
    0.442, 0.197, 0.19, 0.2, 0.25)), row.names = c(NA, -15L), class = "data.frame")