Chapter 20.10, Problem 9P

A nine character long password is to be created using lower-case letters, four special characters {!, @, #, $} and digits. For the password to be valid, it must contain at least one lower-case letter, one of the given special characters and one digit. What is the probability that a randomly generated nine character password is valid? Assume that the password is generated using only the lower-case letters, the given special characters and digits

Please solve the following problem.      Quiz = Pass Quiz = Fail AI = Fail 0.1 0.2 AI = Pass 0.6 0.1     Mid = Pass Mid = Fail AI = Fail 0.2 0.2 AI = Pass 0.5 0.1   Suppose you have three events AI Grade, Quiz, and Mid. Here each event has two possible outcomes, either pass or fail. Additionally, given that AI Grade is observed, Quiz and Mid become independent of each other. Also, out of every 100 students, 30 students fail the AI course. Now, using the joint probability tables given, calculate P(AI Grade=Pass, Quiz=Fail, Mid=Fail).

Consider a database buffer manager that uses 1GB of main memory andkeeps data on a hard drive which reads 100MB per second and takes 10 milliseconds per disk seek. (a)  Assume that (1) the size of each disk block is 10KB and (2) for each block keptin the buffer, the probability that the buffer manager can handle the next data request usingthat block (i.e., the probability that the block contains the requested data) is 5 · 10-6. Inthis case, calculate the expected data access time (i.e., how much time the buffer manageron average would spend to provide a requested disk block). For this calculation, assume that(1) the buffer manager runs the algorithm explained in Section 13.5.1 of the textbook, (2) thebuffer is already full (i.e., the entirety of the 1GB buffer space is already used to hold 105 diskblocks), and (3) no disk blocks are updated (i.e., no need to write dirty blocks back to thehard drive). Also, ignore the time spent for reading/writing data in the main memory.(b)  Assume…