As a construction engineer for a city, you are responsible for ensuring that the company that is providing gravel for a new road puts as much gravel in each truckload as they claim to. You plan to measure the volume of gravel in an SRS of 25 trucks to make sure that the company isn't delivering less gravel per truckload than they claim. Each truckload is supposed to have 20 m of gravel, so you will test the hypotheses Ho: u = 20 verses Ha: u 

a. Describe a Type I error in this context. 

b. Describe a Type II error in this context. 

c. The random sample of 25 trucks yields a sample mean of 19.25 and sample standard deviation of 2.5. Does the sample provide convincing evidence that the company is delivering less gravel per truckload than it should? Perform the above hypothesis test at the given significance level to answer the question. d. Based on your result from part (c), what type of error is possible?