In Machine learning subject

1. What is the main difference between a kNN decision boundary and a decision tree boundary?

2. Suppose we have two dice; one is fair and the other always comes up 6. We toss a biased coin to decide which die to roll. The coin comes up heads with probability p. If the coin turns up heads, we will toss the fair die and if the coin turns up tails, we will toss the other die. Let x be the value of the die roll obtained under this process. (Include p as part of the expression.) (a) What is the expectation of x? (b) What is the variance of x?