Question

A project has three activities A, B, and C that must be carried out sequentially.

----- A -----> ----B----> ------C------>

The probability distributions of the times required to complete each of the activities A, B, and C are uniformly distributed in intervals (1,5], (2,8] and (3,6] days respectively.

The project completion time is the sum of times to finish all three activities.

Run 1000 simulation trials in Excel to simulate the project.

Which of the following Excel functions would generate a duration of activity A, which has a uniform distribution between 2 and 8 days?

Select one:

a. 5* RAND()

b. 1 + 4 * RAND()

c. NORM.INV(RAND(),5,1)

d. NORM.INV(RAND(),1,5)

e. 2 + 6 * RAND()

Answer 1

Answer: Option e. 2 + 6 * RAND()

The RAND() function uniformly generates a number between 0 and 1. Multiplying it by 6 will uniformly generate a number between 0 and 6. Adding 2 to the product will uniformly generate a number between 2 and 8. Hence option e is the correct answer.

Option a generates a number between 0 and 5. Hence it is incorrect.

Option b generates a number between 1 and 5. Hence it is incorrect.

Option c and d generate a random number using a normal distribution. Hence they are incorrect.

Hence, option e is the only correct answer.