For Exercise 4.109, see page 220; for 4.110, see page 223; for 4.111 to 4.114, see page 228; for 4.115, see page 230; and for 4.116 to 4.118, see page 235.

Question 4.113

4.113 Managing a new-product development process.

Managers often have to oversee a series of related activities directed to a desired goal or output. As a new-product development manager, you are responsible for two sequential steps of the product development process—namely, the development of product specifications followed by the design of the manufacturing process. Let be the number of weeks required to complete the development of product specifications, and let be the number of weeks required to complete the design of the manufacturing process. Based on experience, you estimate the following probability distribution for the first step:

Weeks 1 2 3
Probability 0.3 0.5 0.2

For the second step, your estimated distribution is

Weeks 1 2 3 4 5
Probability 0.1 0.15 0.4 0.30 0.05
  1. Calculate and .
  2. The cost per week for the activity of developing product specifications is $8000, while the cost per week for the activity of designing the manufacturing process is $30,000. Calculate the mean cost for each step.
  3. Calculate the mean completion time and mean cost for the two steps combined.

4.113

(a) (b) (c)