Advanced Business Statistics

1. A computer virus is infecting the computers of employees at a large clothing manufacturer. It is established that 25% of computers are infected. The IT specialist randomly selects a sample of eight computers. The probability that none of these 8 computers are infected is:
2. The probability that at most 2 of these 8 computers are infected is:
3. The normal distribution function. The area between z- scores of 1.52 and 2.78 is
4. The lifetimes of a certain brand of pool pumps have an average span of 3 years with a standard deviation of 6 months. What percentage of these pumps is expected to last between 2 and 3.5 years?
5. If the company that sells these pumps wishes that no more than 5% of them are to be replaced, what must be the approximate maximum warranty period?