Hello, this is my brother's homework. I'm a little bit confused since I studied this lesson a long time ago..Can someone help me? I am not sure about my answer..

These box plots show the number of electoral votes one by democratic and republican presidential candidates for the elections from 1984 through 2012. which statement best compares the spread of the data sets

Jack has to solve the problem 281-266.how would you tell him to solve the problem ? tell which strategy you would use ,and solve the problem.

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).