1. In clinical trials a certain drug has an 8% success rate of curing a known disease. If 8 people are known to have the disease. What is the probability of:

a. at least 2 being cured? b. all 8 being cured? c. less than 4 being cured?

2. A computer manufacturer leases computers to customers and provides engineering maintenance. Service call records indicate that 65% of the service calls involve failures in input-output equipment, 25% result from operation errors, and 10% arises from failures in the processing unit. If service calls vary randomly with respect to source of failure, what is the probability that:

a. in the next 7 service calls, 3 involve input-output units, 3 from operation errors, and one from a faulty processing unit?

b. in the next 10 service calls, 0 involve operation errors?

c. in the next 8 service calls, all involve failures in input-output equipment?