When a new machine is functioning properly, only 3% of the items produced are defective. Assume that we will randomly select two parts produced on the machine and that we are interested in number of defective parts found.

a. Describe the conditions under which this situation would be a binomial experiment.

b. Draw the tree diagram to show this problem as a two-trial experiment.

c. How many experimental outcomes result in exactly one defect being found?

d. Compute the probabilities associated with finding no defects, exactly one defect and two defects.

In 2011, New York city had a total of 11,232 motor vehicle accidents that occurred on Monday through Friday between the hours of 3 pm to 6 pm (New York state department of Motor Vehicle website =, October 24, 2012). This corresponds to mean of 14.4 accidents per hour.

a.Compute the probability of no accidents in a 15-minute period

b.Compute the probability of at least one accident in a 15-minute period

c.Compute the probability of 4 or more accidents in a 15-minute period