I have stats questions I need help with

Name: Date: 8. The Screen Actors Guild (SAG) claims that the mean age of actresses when they win Oscars is 33 years. A random sample of 81 Oscar-winning actresses is selected. The sample has a mean of 35.9 years with a standard deviation of 11.1 years. With a = 0.01, is there enough evidence to support SAG's claim? 9. It has been reported that 18% of all high school seniors in the United States have smoked marijuana at least one time in the last month. However, the headmaster of a private boarding school claims that the rate is much lower for his school. He randomly selects 400 students for testing and finds that 62 test positive for marijuana. With a = 0.05, is there enough evidence to support the headmaster's claim