e could simply remember each number as the user entered it 
and use built-in functions to compute the sum and count at
the end.
</font><pre><font size="4" color="blue">
numlist = list()
while ( True ) :
    inp = raw_input('Enter a number: ')
    if inp == 'done' : break
    value = float(inp)
    numlist.append(value)

average = sum(numlist) / len(numlist)
print 'Average:', average
</font></pre><font color="black">We make an empty list before the loop starts, and then each time we have 
a number, we append