Colin asked some of his classmates how many minutes they spent working on their math homework last night. He created a dot plot to show his results. What is the range of the data Colin collected?
20
11
25
5

Assume that there is a 11% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?