10.1 Null and alternative hypotheses

The mean number of years Americans work before retiring is 34.At most 60% of Americans vote in presidential elections.The mean starting salary for San Jose State University graduates is at least $100,000 per year.Twenty-nine percent of high school seniors get drunk each month.Fewer than 5% of adults ride the bus to work in Los Angeles.The mean number of cars a person owns in her lifetime is not more than ten.About half of Americans prefer to live away from cities, given the choice.Europeans have a mean paid vacation each year of six weeks.The chance of developing breast cancer is under 11% for women.Private universities' mean tuition cost is more than $20,000 per year.