Answer:
The variance estimate of this activity is 4.
Explanation:
Given information: One of the activities on the critical path has
Optimistic time = 5 minutes
Most likely time = 6 minutes
Pessimistic time = 17 minutes
The variance estimate of a activity is

where,
is pessimistic time of that activity and
is optimistic time of that activity.
The variance estimate of the given activity is




Therefore the variance estimate of this activity is 4.