*
* Example CELLFONE.DAT from pp 123-125
*
open data cellfone.dat
data(format=free,org=columns) 1 10 y x
*
scatter(style=lines,footer="Figure 3-12 (a) Nonlinear growth in cell phones")
# x y
scatter(style=lines,vlog=10.0,footer="Figure 3-12 (b) Nonlinear growth in logs of cell phones")
# x y
scatter(style=lines,vlog=10.0,hlog=2.0,footer="Figure 3-12 (c) Nonlinear growth in log-log of cell phones")
# x y
*
set logy = log(y)
set logx = log(x)
*
linreg logy
# constant logx
*
* Extend logx through entry 20
*
set logx 11 20 = log(t)
*
* Compute fitted values over periods 11 to 20
*
prj logfit 11 20
set fit 11 20 = exp(logfit)
*
print 11 20 logfit fit