Say a hacker has a list of ndistinct password candidates, only one of which will successfully log her into a secure system.
a. if she tries passwords from the list at random, deleting those passwords that do not work, what is the probability that her first successful login will be (exactly) on her k-th try?

b. now say the hacker tries passwords from the list at random, but does notdelete previously tried passwords from the list. she stops after her first successful login attempt. what is the probability that her first successful login will be (exactly) on her k-th try?

Many everyday occurrences can be represented as a binary bit. for example, a door is open or closed, the stove is on or off, and the fog is asleep or awake. could relationships be represented as a binary value? give example.

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Report all segments of identity by descent longer than 20 polymorphisms between pairs of individuals in the following cohort of 15 individuals across 49 polymorphisms: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 numeric input 2 points possible (graded) you have 2 attempts to complete the assignment below. for example if the sequence is "bcd", which occurs in "abcdef" , the starting point would be 2 (b), and the finishing point would be 4(d). individuals 7,10 between positions