4. An array of n distinct keys were inserted into a hash table of size m sequentially over n time slots, suppose chaining was used to resolve collisions, let Xk be the random variable of the number of elements examined when searching for the k-th inserted key(the key inserted in the k-th time slot, 1-k-n) i),i2 0? (a) what is the probability mass function of Xk, .e., calculate P(X (b) what is the expected value of X? (c) what is the expected number of elements examined when searching for a key randomly selected from the array? 4. An array of n distinct keys were inserted into a hash table of size m sequentially over n time slots, suppose chaining was used to resolve collisions, let Xk be the random variable of the number of elements examined when searching for the k-th inserted key(the key inserted in the k-th time slot, 1-k-n) i),i2 0? (a) what is the probability mass function of Xk, .e., calculate P(X (b) what is the expected value of X? (c) what is the expected number of elements examined when searching for a key randomly selected from the array