*Does U-turn*
OK, you right.
Considering the accuracy of the output is 6 DP (by hint format), i assume that means 1,000,001 possible outputs if you include 0 and 1, each with the same probability. My 100,000 test was probably not likely to yield a 0.000 000 or 1.000 000. Searching the interweb confirms range [0,1]