clear
set obs 100
gen firm_size = uniform()
cumul firm_size,g(var2) eq
recode var2 (min/0.1=1)(0.1/0.2=2)(0.2/0.3=3)(0.3/0.4=4)(0.4/0.5=5)(0.5/0.6=6)(0.6/0.7=7)(0.7/0.8=8)(0.8/0.9=9)(0.9/max=10)
egen size_mean1 = mean(firm_size),by(var2)
***or
egen var3 = cut(firm_size),group(10)
egen size_mean2 = mean(firm_size),by(var3)