Scrum consists of three main roles:
Product Owner: Product Owner usually represents the Client and acts as a point of contact from the Client side. The one who prioritizes the list of Product Backlogs which Scrum Team should finish and release.
Scrum Master: Scrum Master acts as a facilitator to the Scrum Development Team. Clarifies the queries and organizes the team from distractions and teach the team how to use scrum and also concentrates on Return on Investment (ROI). Responsible for managing the sprint.
Scrum Development Team: Developer’s, QA’s. Who develops the product. Scrum development team decides the effort estimation to complete a Product Backlog Item.
Scrum Team: A cross-functional, self-organizing group of dedicated people (Group of Product Owner, Business Analyst, Developer’s and QA’s). The recommended size of a scrum team is 7 plus or minus 2 (i.e, between 5 to 9 members in a team).