Final answer:
The distribution used by PERT analysis to calculate expected activity times and variances is the Beta distribution.
Step-by-step explanation:
The distribution used by PERT analysis to calculate expected activity times and variances is the Beta distribution. The Beta distribution is a continuous probability distribution that is used to model uncertain events with a fixed beginning and end point. It is commonly used in project management to estimate the time required to complete activities.
The Beta distribution is particularly useful in PERT analysis because it allows for a range of possible outcomes, rather than assuming a single, fixed value for the activity time. This allows for a more realistic representation of the uncertainties and risks involved in project scheduling.