Do you see any problems with the choice of hash functions in 4.4.1? What advice could you give…

Do you see any problems with the choice of hash functions in  4.4.1? What advice could you give someone who was going to use a hash function of the form h(x) = ax + b mod 2k ? Section 4.5  4.5.1 : Compute the surprise number (second moment) for the stream 3, 1, 4, 1, 3, 4, 2, 1, 2. What is the third moment o