gnuplot histogram and normal distribution

histogram.plot

set key left box
set autoscale
set samples 800
set terminal postscript eps enhanced size 3in,3in color


set x2range [-10 : 8]
set ytics nomirror
set y2tics
set autoscale  y
set autoscale y2

invsqrt2pi = 0.398942280401433
normal(x,mu,sigma)=sigma<=0?1/0:invsqrt2pi/sigma*exp(-0.5*((x-mu)/sigma)**2)

binwidth=0.3
bin(x,width)=width*floor(x/width)
plot 'var.dat' using (bin($1,binwidth)):(1.0) smooth freq with boxes notitle, \
     normal(x,0,1.4) axes x2y2 with lines lw 2 notitle

#     normal(x,0,1) axes x2y2 with lines lw 2 title "a good fit", \

set key left box
set autoscale
set samples 800
set terminal postscript eps enhanced size 3in,3in color

set x2range [-10 : 8]
set ytics nomirror
set y2tics
set autoscale y
set autoscale y2

invsqrt2pi = 0.398942280401433
normal(x,mu,sigma)=sigma<=0?1/0:invsqrt2pi/sigmaexp(-0.5((x-mu)/sigma)**2)

binwidth=0.3
bin(x,width)=width*floor(x/width)
plot 'var.dat' using (bin($1,binwidth)):(1.0) smooth freq with boxes notitle,
normal(x,0,1.4) axes x2y2 with lines lw 2 notitle