Originally Posted by

**CaptainBlack** No need to check the question the clue is in the precision of the log-on probability. This is given to two significant figures, no naively we might expect that we should give the answer two significant figures or 0.021.

But wait I hear you cry, a probability of 0.97 indicates a range of possible values of 0.965 to 0.975 (give or take an end point). That gives a range for the answer of 0.0277 to 0.0150, so we have at best only one significant figure, so the answer should be truncated to 0.02.

CB