pls help with d-f

The manager of a local youth sports organization is planning its soccer season. The activities, their immediate predecessors, and the activity time estimates (in weeks) are as follows. (a) Draw the project network diagram. (b) Compute the mean and variance of the duration of each activity. You may do this by hand or by using technology, such as Excel. (c) Determine the critical path, the expected project completion time, and the variance of the project completion time. (d) What is the probability that the planning process is completed within 12.1 weeks? (e) What is the probability that the planning process takes longer than 14.2 weeks to complete? (f) If the manager wants a 94.5% probability of completing the planning process on time, how far ahead of the first practice should they start working