A company is investigating the average manufacturing times of two different manufacturing processes, denoted Process 1 and Process 2. Independent random samples have been selected from each process and the results (in minutes) are shown below together with information on population standard deviations.

Process 1Process 2

Sample Size2229

Sample Mean1314

Population standard deviation67

1. a) [10 marks] Use the 10% level of significance and the p-value approach to determine if the average manufacturing time for Process 1 is lower than the average manufacturing time for Process 2.

1. b) [4 marks] Construct a 99% confidence interval estimate of thedifference between the average manufacturing times of the two processes.