A box includes 25 lamps. We know that from every 5 lamps of this kind 1 is

defective. Let X be the number of lamps that are defective in the box.

a) Write the probability model for X and use formula and calculate the probability that exactly 3 lamps in this box are defective. Use 3 decimal places.

b) Use Minitab and calculate the probability that at most 5 lamps in this box are defective? Use 3 decimal places.