The article "Predicting Profit Performance for Selecting Candidate International Construction Projects" (S. Han, D. Kim, and H. Kim, Journal of Construction Engineering and Management Science, 2007: 425-436) presents an analysis of the profit of international construction projects. In a sample of 126 projects, the average profit margin (in percent) was 8.24 with a standard deviation of 16.33. A test is made of H0 :μ ≥ 10 versus H1 :μ < 10.
a. Find the P-value.
b. Do you believe that it is plausible that the mean profit margin is at least 10%, or are you convinced that it is less than 10%? Explain your reasoning.