Part a) (7 marks) Conduct a hypothesis testing, given that: =15, n=100, =48, =0.1. H0: =50 H1: <50 Part b) (9 marks) The sample mean and standard deviation from a random sample of 10 observations from a normal population were computed as =23 and s=9. Determine whether there is enough evidence to infer at the 10% significance level that the population means is great than 20.