Problem
Petite Company operates in the toys manufacturing industry. The company produces wooden toys for 3 to 6 years old kids. A study of Petite Company's practice regarding the order of raw materials revealed that on average a purchase order takes 14 days to be completed. The standard deviation equaled 3.6 days. Assume that a sample of 30 purchase orders was selected. What is the probability that on average the sample purchase orders are completed for less than 12 days?