A violin student records the number of hours she spends practicing during each of nine consecutive weeks: 6.2

5.0

4.3

7.4

5.8

7.2

8.4

1.2

6.3

What is the mean number of hours spent practicing per week during this period?

The discrete random variables x and y take integer values with joint probability distribution given by f (x, y) = a(y−x+1) 0 ≤ x ≤ y ≤ 2 or =0 otherwise, where a is a constant. 1 tabulate the distribution and show that a = 0.1.2 find the marginal distributions of x and y. 3 calculate cov(x, y).4 state, giving a reason, whether x and y are independent. 5 calculate e(y|x = 1).