I am stuck on one thing. I need to know the probability that a project is 1 day late. I am using a CPM(Critical Path Method). It says to use NORMDIST or NORMINV function. Example is (N(CT,PSD)). The critical time is 15.5, project variance is 1.3611111111 and standard deviation is 1.1666667. Any ideas? I created a chart with Activities, Durations, Slacks, Critical Activities and Task Variaince. Thanks.