The cooling system in a nuclear submarine consists of an assembly pipe through which a coolant is circulated. Specifications require that weld strength must meet or exceed 150 psi.
(a) Suppose the designers decide to test the hypothesis H0:  = 150 versus H1:  > 150. Explain why this choice of alternative is preferable to H1:  < 150
(b) A random sample of 20 welds results in = 153.7 psi and s = 11.5 psi. What conclusions can you draw about the hypothesis in part (a)? Use  = 0.05.