According to recent statistics, the people with the most friends on Facebook (the top 15%) has an average of 520 Facebook friends. For a statistics project a student at San Jose State College tests the hypothesis that SJSU students will average more than 520 Facebook friends.

She randomly selects 3 classes from the schedule of classes and distributes a survey in these classes. Her sample contains 45 students.

Here are the null and alternative hypotheses for her study: H0: µ = 520, Ha: µ > 520.

What does µ represent in these hypotheses?