How to make boundaries with numpy at mathplot lib

I am trying to generate random numbers from -0.005 to 0.005 and want to give position from 0 to box size

enter code here
import Numpy as np

 a= []
 velocities= np.random.random(a)
 [a=> -0.005]
 [a<  0.005]
 print(velocities)

 box_size=1 
 b=[0,box size]
 positions = np.random.random(b)