01). (8-9-17 marks) (Parta and bare separate questions) Part (a) (8 marks) A certain tensile test was performed on 25 specimens of a certain type of steel alloy pipe. The analysis of sample data revealed that the sample mean is = 1.25 and the sample standard deviation is s=025.compute a 98% lower confidence bound on the true average tensile strength. State any necessary assumptions about the underlying distribution of the data and interpret the result. Part (b) 19 marks) Two types of plastic are suitable for use by an electronics component manufacturer. The breaking strength of this plastic is important. It is known that o = 6 = 1.0 psi. From a random sample of size m = 10 and = 12, we obtain , = 162.5 and 7: = 155. The company will not adopt plastic / unless its mean breaking strength exceeds that of plastic 2. Based on the sample information, should it use plastic I? Use a = 0.1 in reaching a decision. State any assumptions made in reaching your decision