cohen_d_height.R

# http://www.cdc.gov/nchs/data/nhsr/nhsr010.pdf

n_fem = 604
h_fem = 162.2
se_fem = 0.34
sd_fem = se_fem * sqrt(n_fem)

n_mal = 591
h_mal = 176.6
se_mal = 0.38
sd_mal = se_mal * sqrt(n_mal)

pooled_sd_height <- sqrt((n_fem*sd_fem^2 + n_mal*sd_mal^2)/(n_mal+n_fem))

(h_mal-h_fem)/pooled_sd_height
# [1] 1.635762

cohen_d_vtl.R

library(plyr)
length_mean <- ddply(length_est, .(Sex), summarise, 
                     est1_mean = mean(est1),
                     est1_sd = sd(est1),
                     N = length(File))
length_mean
#   Sex est1_mean  est1_sd   N
# 1   f  14.90808 1.107414 201
# 2   m  16.98004 1.354225 149

pooled_sd <- with(length_mean, 
                  sqrt(sum((N-1)*(est1_sd^2))/sum(N))
                  )

abs(diff(length_mean$est1_mean)) / pooled_sd
# [1] 1.705293