Let hours (x) denote the number of hours of sleep a student got before taking a homework, and let score (Y) denote his score on the test (0-100)

1) Write down a bivariate regression equation that connects Y and X. Do not forget to include u (the unobserved error)

2) what kinds of factors are contained in u? are these likely to be correlated with the amount of sleep?

3) Homework scores? Explain.