set verbose off
open mroz87.gdt --quiet

series lWW = log(WW)
scalar m = mean(lWW)
scalar s = sd(lWW)

###
### prepare matrix with data for plot
###

# number of valid observations
scalar n = nobs(lWW)
# discretize log wage
scalar k = 4
series disc_lWW = round(lWW*k)/k
# get frequencies
matrix f = aggregate(null, disc_lWW)
# add density
phi = dnorm((f[,1] - m)/s) / (s*k)
# put columns together and add labels
plotmat = f[,2]./n ~ phi  ~ f[,1]
strings cnames = defarray("frequency", "density", "log wage")
cnameset(plotmat, cnames)

###
### create plot
###

plot plotmat
    # move legend
    literal set key outside rmargin
    # set line style
    literal set linetype 2 dashtype 2 linewidth 2
    # set histogram color
    literal set linetype 1 lc rgb "#777777"
    # set histogram style
    literal set style fill solid 0.25 border
    # set histogram width
    printf "set boxwidth %4.2f\n", 0.5/k
    options with-lines=2 with-boxes=1
end plot --output=display