An online education platform, "EduMax," wants to evaluate the effectiveness of a new feature that allows students to submit assignments through a mobile app. The platform has 20,000 active users, and to collect feedback, the company randomly selects 500 students. Instead of sending the survey to the selected 500 students, a technical issue caused the survey to be sent only to students who had logged into the platform within the last week. As a result, the survey was completed by 300 students who are all recent users of the platform. The average satisfaction rating for the new feature is 8.9 , and the company concludes that the feature is highly effective.